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lightning-sunbird  0.9+nobinonly
Functions
select.c File Reference
#include "sqliteInt.h"

Go to the source code of this file.

Functions

static void clearSelect (Select *p)
Selectsqlite3SelectNew (ExprList *pEList, SrcList *pSrc, Expr *pWhere, ExprList *pGroupBy, Expr *pHaving, ExprList *pOrderBy, int isDistinct, Expr *pLimit, Expr *pOffset)
void sqlite3SelectDelete (Select *p)
int sqlite3JoinType (Parse *pParse, Token *pA, Token *pB, Token *pC)
static int columnIndex (Table *pTab, const char *zCol)
static void setToken (Token *p, const char *z)
static ExprcreateIdExpr (const char *zName)
static void addWhereTerm (const char *zCol, const Table *pTab1, const char *zAlias1, const Table *pTab2, const char *zAlias2, int iRightJoinTable, Expr **ppExpr)
static void setJoinExpr (Expr *p, int iTable)
static int sqliteProcessJoin (Parse *pParse, Select *p)
static void pushOntoSorter (Parse *pParse, ExprList *pOrderBy, Select *pSelect)
static void codeOffset (Vdbe *v, Select *p, int iContinue, int nPop)
static void codeDistinct (Vdbe *v, int iTab, int addrRepeat, int N)
static int selectInnerLoop (Parse *pParse, Select *p, ExprList *pEList, int srcTab, int nColumn, ExprList *pOrderBy, int distinct, int eDest, int iParm, int iContinue, int iBreak, char *aff)
static KeyInfokeyInfoFromExprList (Parse *pParse, ExprList *pList)
static void generateSortTail (Parse *pParse, Select *p, Vdbe *v, int nColumn, int eDest, int iParm)
static const char * columnType (NameContext *pNC, Expr *pExpr, const char **pzOriginDb, const char **pzOriginTab, const char **pzOriginCol)
static void generateColumnTypes (Parse *pParse, SrcList *pTabList, ExprList *pEList)
static void generateColumnNames (Parse *pParse, SrcList *pTabList, ExprList *pEList)
static const char * selectOpName (int id)
static int prepSelectStmt (Parse *, Select *)
Tablesqlite3ResultSetOfSelect (Parse *pParse, char *zTabName, Select *pSelect)
static int matchOrderbyToColumn (Parse *pParse, Select *pSelect, ExprList *pOrderBy, int iTable, int mustComplete)
Vdbesqlite3GetVdbe (Parse *pParse)
static void computeLimitRegisters (Parse *pParse, Select *p, int iBreak)
static void createSortingIndex (Parse *pParse, Select *p, ExprList *pOrderBy)
static CollSeqmultiSelectCollSeq (Parse *pParse, Select *p, int iCol)
static int multiSelect (Parse *pParse, Select *p, int eDest, int iParm, char *aff)
static void substExprList (ExprList *, int, ExprList *)
static void substSelect (Select *, int, ExprList *)
static void substExpr (Expr *pExpr, int iTable, ExprList *pEList)
static int flattenSubquery (Select *p, int iFrom, int isAgg, int subqueryIsAgg)
static int simpleMinMaxQuery (Parse *pParse, Select *p, int eDest, int iParm)
static int processOrderGroupBy (NameContext *pNC, ExprList *pOrderBy, const char *zType)
int sqlite3SelectResolve (Parse *pParse, Select *p, NameContext *pOuterNC)
static void resetAccumulator (Parse *pParse, AggInfo *pAggInfo)
static void finalizeAggFunctions (Parse *pParse, AggInfo *pAggInfo)
static void updateAccumulator (Parse *pParse, AggInfo *pAggInfo)
int sqlite3Select (Parse *pParse, Select *p, int eDest, int iParm, Select *pParent, int parentTab, int *pParentAgg, char *aff)

Function Documentation

static void addWhereTerm ( const char *  zCol,
const Table pTab1,
const char *  zAlias1,
const Table pTab2,
const char *  zAlias2,
int  iRightJoinTable,
Expr **  ppExpr 
) [static]

Definition at line 201 of file select.c.

 {
  Expr *pE1a, *pE1b, *pE1c;
  Expr *pE2a, *pE2b, *pE2c;
  Expr *pE;

  pE1a = createIdExpr(zCol);
  pE2a = createIdExpr(zCol);
  if( zAlias1==0 ){
    zAlias1 = pTab1->zName;
  }
  pE1b = createIdExpr(zAlias1);
  if( zAlias2==0 ){
    zAlias2 = pTab2->zName;
  }
  pE2b = createIdExpr(zAlias2);
  pE1c = sqlite3Expr(TK_DOT, pE1b, pE1a, 0);
  pE2c = sqlite3Expr(TK_DOT, pE2b, pE2a, 0);
  pE = sqlite3Expr(TK_EQ, pE1c, pE2c, 0);
  ExprSetProperty(pE, EP_FromJoin);
  pE->iRightJoinTable = iRightJoinTable;
  *ppExpr = sqlite3ExprAnd(*ppExpr, pE);
}

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static void clearSelect ( Select p) [static]

Definition at line 24 of file select.c.

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static void codeDistinct ( Vdbe v,
int  iTab,
int  addrRepeat,
int  N 
) [static]

Definition at line 417 of file select.c.

 {
  sqlite3VdbeAddOp(v, OP_MakeRecord, -N, 0);
  sqlite3VdbeAddOp(v, OP_Distinct, iTab, sqlite3VdbeCurrentAddr(v)+3);
  sqlite3VdbeAddOp(v, OP_Pop, N+1, 0);
  sqlite3VdbeAddOp(v, OP_Goto, 0, addrRepeat);
  VdbeComment((v, "# skip indistinct records"));
  sqlite3VdbeAddOp(v, OP_IdxInsert, iTab, 0);
}

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static void codeOffset ( Vdbe v,
Select p,
int  iContinue,
int  nPop 
) [static]

Definition at line 389 of file select.c.

 {
  if( p->iOffset>=0 && iContinue!=0 ){
    int addr;
    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iOffset);
    addr = sqlite3VdbeAddOp(v, OP_IfMemNeg, p->iOffset, 0);
    if( nPop>0 ){
      sqlite3VdbeAddOp(v, OP_Pop, nPop, 0);
    }
    sqlite3VdbeAddOp(v, OP_Goto, 0, iContinue);
    VdbeComment((v, "# skip OFFSET records"));
    sqlite3VdbeJumpHere(v, addr);
  }
}

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static int columnIndex ( Table pTab,
const char *  zCol 
) [static]

Definition at line 170 of file select.c.

                                                     {
  int i;
  for(i=0; i<pTab->nCol; i++){
    if( sqlite3StrICmp(pTab->aCol[i].zName, zCol)==0 ) return i;
  }
  return -1;
}

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static const char* columnType ( NameContext pNC,
Expr pExpr,
const char **  pzOriginDb,
const char **  pzOriginTab,
const char **  pzOriginCol 
) [static]

Definition at line 787 of file select.c.

 {
  char const *zType = 0;
  char const *zOriginDb = 0;
  char const *zOriginTab = 0;
  char const *zOriginCol = 0;
  int j;
  if( pExpr==0 || pNC->pSrcList==0 ) return 0;

  /* The TK_AS operator can only occur in ORDER BY, GROUP BY, HAVING,
  ** and LIMIT clauses.  But pExpr originates in the result set of a
  ** SELECT.  So pExpr can never contain an AS operator.
  */
  assert( pExpr->op!=TK_AS );

  switch( pExpr->op ){
    case TK_AGG_COLUMN:
    case TK_COLUMN: {
      /* The expression is a column. Locate the table the column is being
      ** extracted from in NameContext.pSrcList. This table may be real
      ** database table or a subquery.
      */
      Table *pTab = 0;            /* Table structure column is extracted from */
      Select *pS = 0;             /* Select the column is extracted from */
      int iCol = pExpr->iColumn;  /* Index of column in pTab */
      while( pNC && !pTab ){
        SrcList *pTabList = pNC->pSrcList;
        for(j=0;j<pTabList->nSrc && pTabList->a[j].iCursor!=pExpr->iTable;j++);
        if( j<pTabList->nSrc ){
          pTab = pTabList->a[j].pTab;
          pS = pTabList->a[j].pSelect;
        }else{
          pNC = pNC->pNext;
        }
      }

      if( pTab==0 ){
        /* FIX ME:
        ** This can occurs if you have something like "SELECT new.x;" inside
        ** a trigger.  In other words, if you reference the special "new"
        ** table in the result set of a select.  We do not have a good way
        ** to find the actual table type, so call it "TEXT".  This is really
        ** something of a bug, but I do not know how to fix it.
        **
        ** This code does not produce the correct answer - it just prevents
        ** a segfault.  See ticket #1229.
        */
        zType = "TEXT";
        break;
      }

      assert( pTab );
#ifndef SQLITE_OMIT_SUBQUERY
      if( pS ){
        /* The "table" is actually a sub-select or a view in the FROM clause
        ** of the SELECT statement. Return the declaration type and origin
        ** data for the result-set column of the sub-select.
        */
        if( iCol>=0 && iCol<pS->pEList->nExpr ){
          /* If iCol is less than zero, then the expression requests the
          ** rowid of the sub-select or view. This expression is legal (see 
          ** test case misc2.2.2) - it always evaluates to NULL.
          */
          NameContext sNC;
          Expr *p = pS->pEList->a[iCol].pExpr;
          sNC.pSrcList = pS->pSrc;
          sNC.pNext = 0;
          sNC.pParse = pNC->pParse;
          zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol); 
        }
      }else
#endif
      if( pTab->pSchema ){
        /* A real table */
        assert( !pS );
        if( iCol<0 ) iCol = pTab->iPKey;
        assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
        if( iCol<0 ){
          zType = "INTEGER";
          zOriginCol = "rowid";
        }else{
          zType = pTab->aCol[iCol].zType;
          zOriginCol = pTab->aCol[iCol].zName;
        }
        zOriginTab = pTab->zName;
        if( pNC->pParse ){
          int iDb = sqlite3SchemaToIndex(pNC->pParse->db, pTab->pSchema);
          zOriginDb = pNC->pParse->db->aDb[iDb].zName;
        }
      }
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_SELECT: {
      /* The expression is a sub-select. Return the declaration type and
      ** origin info for the single column in the result set of the SELECT
      ** statement.
      */
      NameContext sNC;
      Select *pS = pExpr->pSelect;
      Expr *p = pS->pEList->a[0].pExpr;
      sNC.pSrcList = pS->pSrc;
      sNC.pNext = pNC;
      sNC.pParse = pNC->pParse;
      zType = columnType(&sNC, p, &zOriginDb, &zOriginTab, &zOriginCol); 
      break;
    }
#endif
  }
  
  if( pzOriginDb ){
    assert( pzOriginTab && pzOriginCol );
    *pzOriginDb = zOriginDb;
    *pzOriginTab = zOriginTab;
    *pzOriginCol = zOriginCol;
  }
  return zType;
}

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static void computeLimitRegisters ( Parse pParse,
Select p,
int  iBreak 
) [static]

Definition at line 1482 of file select.c.

                                                                       {
  Vdbe *v = 0;
  int iLimit = 0;
  int iOffset;
  int addr1, addr2;

  /* 
  ** "LIMIT -1" always shows all rows.  There is some
  ** contraversy about what the correct behavior should be.
  ** The current implementation interprets "LIMIT 0" to mean
  ** no rows.
  */
  if( p->pLimit ){
    p->iLimit = iLimit = pParse->nMem;
    pParse->nMem += 2;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pLimit);
    sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iLimit, 0);
    VdbeComment((v, "# LIMIT counter"));
    sqlite3VdbeAddOp(v, OP_IfMemZero, iLimit, iBreak);
  }
  if( p->pOffset ){
    p->iOffset = iOffset = pParse->nMem++;
    v = sqlite3GetVdbe(pParse);
    if( v==0 ) return;
    sqlite3ExprCode(pParse, p->pOffset);
    sqlite3VdbeAddOp(v, OP_MustBeInt, 0, 0);
    sqlite3VdbeAddOp(v, OP_MemStore, iOffset, p->pLimit==0);
    VdbeComment((v, "# OFFSET counter"));
    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iOffset, 0);
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp(v, OP_Integer, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
    if( p->pLimit ){
      sqlite3VdbeAddOp(v, OP_Add, 0, 0);
    }
  }
  if( p->pLimit ){
    addr1 = sqlite3VdbeAddOp(v, OP_IfMemPos, iLimit, 0);
    sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
    sqlite3VdbeAddOp(v, OP_MemInt, -1, iLimit+1);
    addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp(v, OP_MemStore, iLimit+1, 1);
    VdbeComment((v, "# LIMIT+OFFSET"));
    sqlite3VdbeJumpHere(v, addr2);
  }
}

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static Expr* createIdExpr ( const char *  zName) [static]

Definition at line 190 of file select.c.

                                            {
  Token dummy;
  setToken(&dummy, zName);
  return sqlite3Expr(TK_ID, 0, 0, &dummy);
}

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static void createSortingIndex ( Parse pParse,
Select p,
ExprList pOrderBy 
) [static]

Definition at line 1536 of file select.c.

                                                                            {
  if( pOrderBy ){
    int addr;
    assert( pOrderBy->iECursor==0 );
    pOrderBy->iECursor = pParse->nTab++;
    addr = sqlite3VdbeAddOp(pParse->pVdbe, OP_OpenVirtual,
                            pOrderBy->iECursor, pOrderBy->nExpr+1);
    assert( p->addrOpenVirt[2] == -1 );
    p->addrOpenVirt[2] = addr;
  }
}

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static void finalizeAggFunctions ( Parse pParse,
AggInfo pAggInfo 
) [static]

Definition at line 2645 of file select.c.

                                                                  {
  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pF;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    ExprList *pList = pF->pExpr->pList;
    sqlite3VdbeOp3(v, OP_AggFinal, pF->iMem, pList ? pList->nExpr : 0,
                      (void*)pF->pFunc, P3_FUNCDEF);
  }
}

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static int flattenSubquery ( Select p,
int  iFrom,
int  isAgg,
int  subqueryIsAgg 
) [static]

Definition at line 2119 of file select.c.

 {
  Select *pSub;       /* The inner query or "subquery" */
  SrcList *pSrc;      /* The FROM clause of the outer query */
  SrcList *pSubSrc;   /* The FROM clause of the subquery */
  ExprList *pList;    /* The result set of the outer query */
  int iParent;        /* VDBE cursor number of the pSub result set temp table */
  int i;              /* Loop counter */
  Expr *pWhere;                    /* The WHERE clause */
  struct SrcList_item *pSubitem;   /* The subquery */

  /* Check to see if flattening is permitted.  Return 0 if not.
  */
  if( p==0 ) return 0;
  pSrc = p->pSrc;
  assert( pSrc && iFrom>=0 && iFrom<pSrc->nSrc );
  pSubitem = &pSrc->a[iFrom];
  pSub = pSubitem->pSelect;
  assert( pSub!=0 );
  if( isAgg && subqueryIsAgg ) return 0;                 /* Restriction (1)  */
  if( subqueryIsAgg && pSrc->nSrc>1 ) return 0;          /* Restriction (2)  */
  pSubSrc = pSub->pSrc;
  assert( pSubSrc );
  /* Prior to version 3.1.2, when LIMIT and OFFSET had to be simple constants,
  ** not arbitrary expresssions, we allowed some combining of LIMIT and OFFSET
  ** because they could be computed at compile-time.  But when LIMIT and OFFSET
  ** became arbitrary expressions, we were forced to add restrictions (13)
  ** and (14). */
  if( pSub->pLimit && p->pLimit ) return 0;              /* Restriction (13) */
  if( pSub->pOffset ) return 0;                          /* Restriction (14) */
  if( pSubSrc->nSrc==0 ) return 0;                       /* Restriction (7)  */
  if( (pSub->isDistinct || pSub->pLimit) 
         && (pSrc->nSrc>1 || isAgg) ){          /* Restrictions (4)(5)(8)(9) */
     return 0;       
  }
  if( p->isDistinct && subqueryIsAgg ) return 0;         /* Restriction (6)  */
  if( (p->disallowOrderBy || p->pOrderBy) && pSub->pOrderBy ){
     return 0;                                           /* Restriction (11) */
  }

  /* Restriction 3:  If the subquery is a join, make sure the subquery is 
  ** not used as the right operand of an outer join.  Examples of why this
  ** is not allowed:
  **
  **         t1 LEFT OUTER JOIN (t2 JOIN t3)
  **
  ** If we flatten the above, we would get
  **
  **         (t1 LEFT OUTER JOIN t2) JOIN t3
  **
  ** which is not at all the same thing.
  */
  if( pSubSrc->nSrc>1 && iFrom>0 && (pSrc->a[iFrom-1].jointype & JT_OUTER)!=0 ){
    return 0;
  }

  /* Restriction 12:  If the subquery is the right operand of a left outer
  ** join, make sure the subquery has no WHERE clause.
  ** An examples of why this is not allowed:
  **
  **         t1 LEFT OUTER JOIN (SELECT * FROM t2 WHERE t2.x>0)
  **
  ** If we flatten the above, we would get
  **
  **         (t1 LEFT OUTER JOIN t2) WHERE t2.x>0
  **
  ** But the t2.x>0 test will always fail on a NULL row of t2, which
  ** effectively converts the OUTER JOIN into an INNER JOIN.
  */
  if( iFrom>0 && (pSrc->a[iFrom-1].jointype & JT_OUTER)!=0 
      && pSub->pWhere!=0 ){
    return 0;
  }

  /* If we reach this point, it means flattening is permitted for the
  ** iFrom-th entry of the FROM clause in the outer query.
  */

  /* Move all of the FROM elements of the subquery into the
  ** the FROM clause of the outer query.  Before doing this, remember
  ** the cursor number for the original outer query FROM element in
  ** iParent.  The iParent cursor will never be used.  Subsequent code
  ** will scan expressions looking for iParent references and replace
  ** those references with expressions that resolve to the subquery FROM
  ** elements we are now copying in.
  */
  iParent = pSubitem->iCursor;
  {
    int nSubSrc = pSubSrc->nSrc;
    int jointype = pSubitem->jointype;

    sqlite3DeleteTable(0, pSubitem->pTab);
    sqliteFree(pSubitem->zDatabase);
    sqliteFree(pSubitem->zName);
    sqliteFree(pSubitem->zAlias);
    if( nSubSrc>1 ){
      int extra = nSubSrc - 1;
      for(i=1; i<nSubSrc; i++){
        pSrc = sqlite3SrcListAppend(pSrc, 0, 0);
      }
      p->pSrc = pSrc;
      for(i=pSrc->nSrc-1; i-extra>=iFrom; i--){
        pSrc->a[i] = pSrc->a[i-extra];
      }
    }
    for(i=0; i<nSubSrc; i++){
      pSrc->a[i+iFrom] = pSubSrc->a[i];
      memset(&pSubSrc->a[i], 0, sizeof(pSubSrc->a[i]));
    }
    pSrc->a[iFrom+nSubSrc-1].jointype = jointype;
  }

  /* Now begin substituting subquery result set expressions for 
  ** references to the iParent in the outer query.
  ** 
  ** Example:
  **
  **   SELECT a+5, b*10 FROM (SELECT x*3 AS a, y+10 AS b FROM t1) WHERE a>b;
  **   \                     \_____________ subquery __________/          /
  **    \_____________________ outer query ______________________________/
  **
  ** We look at every expression in the outer query and every place we see
  ** "a" we substitute "x*3" and every place we see "b" we substitute "y+10".
  */
  pList = p->pEList;
  for(i=0; i<pList->nExpr; i++){
    Expr *pExpr;
    if( pList->a[i].zName==0 && (pExpr = pList->a[i].pExpr)->span.z!=0 ){
      pList->a[i].zName = sqliteStrNDup((char*)pExpr->span.z, pExpr->span.n);
    }
  }
  substExprList(p->pEList, iParent, pSub->pEList);
  if( isAgg ){
    substExprList(p->pGroupBy, iParent, pSub->pEList);
    substExpr(p->pHaving, iParent, pSub->pEList);
  }
  if( pSub->pOrderBy ){
    assert( p->pOrderBy==0 );
    p->pOrderBy = pSub->pOrderBy;
    pSub->pOrderBy = 0;
  }else if( p->pOrderBy ){
    substExprList(p->pOrderBy, iParent, pSub->pEList);
  }
  if( pSub->pWhere ){
    pWhere = sqlite3ExprDup(pSub->pWhere);
  }else{
    pWhere = 0;
  }
  if( subqueryIsAgg ){
    assert( p->pHaving==0 );
    p->pHaving = p->pWhere;
    p->pWhere = pWhere;
    substExpr(p->pHaving, iParent, pSub->pEList);
    p->pHaving = sqlite3ExprAnd(p->pHaving, sqlite3ExprDup(pSub->pHaving));
    assert( p->pGroupBy==0 );
    p->pGroupBy = sqlite3ExprListDup(pSub->pGroupBy);
  }else{
    substExpr(p->pWhere, iParent, pSub->pEList);
    p->pWhere = sqlite3ExprAnd(p->pWhere, pWhere);
  }

  /* The flattened query is distinct if either the inner or the
  ** outer query is distinct. 
  */
  p->isDistinct = p->isDistinct || pSub->isDistinct;

  /*
  ** SELECT ... FROM (SELECT ... LIMIT a OFFSET b) LIMIT x OFFSET y;
  **
  ** One is tempted to try to add a and b to combine the limits.  But this
  ** does not work if either limit is negative.
  */
  if( pSub->pLimit ){
    p->pLimit = pSub->pLimit;
    pSub->pLimit = 0;
  }

  /* Finially, delete what is left of the subquery and return
  ** success.
  */
  sqlite3SelectDelete(pSub);
  return 1;
}

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static void generateColumnNames ( Parse pParse,
SrcList pTabList,
ExprList pEList 
) [static]

Definition at line 948 of file select.c.

 {
  Vdbe *v = pParse->pVdbe;
  int i, j;
  sqlite3 *db = pParse->db;
  int fullNames, shortNames;

#ifndef SQLITE_OMIT_EXPLAIN
  /* If this is an EXPLAIN, skip this step */
  if( pParse->explain ){
    return;
  }
#endif

  assert( v!=0 );
  if( pParse->colNamesSet || v==0 || sqlite3MallocFailed() ) return;
  pParse->colNamesSet = 1;
  fullNames = (db->flags & SQLITE_FullColNames)!=0;
  shortNames = (db->flags & SQLITE_ShortColNames)!=0;
  sqlite3VdbeSetNumCols(v, pEList->nExpr);
  for(i=0; i<pEList->nExpr; i++){
    Expr *p;
    p = pEList->a[i].pExpr;
    if( p==0 ) continue;
    if( pEList->a[i].zName ){
      char *zName = pEList->a[i].zName;
      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, strlen(zName));
      continue;
    }
    if( p->op==TK_COLUMN && pTabList ){
      Table *pTab;
      char *zCol;
      int iCol = p->iColumn;
      for(j=0; j<pTabList->nSrc && pTabList->a[j].iCursor!=p->iTable; j++){}
      assert( j<pTabList->nSrc );
      pTab = pTabList->a[j].pTab;
      if( iCol<0 ) iCol = pTab->iPKey;
      assert( iCol==-1 || (iCol>=0 && iCol<pTab->nCol) );
      if( iCol<0 ){
        zCol = "rowid";
      }else{
        zCol = pTab->aCol[iCol].zName;
      }
      if( !shortNames && !fullNames && p->span.z && p->span.z[0] ){
        sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
      }else if( fullNames || (!shortNames && pTabList->nSrc>1) ){
        char *zName = 0;
        char *zTab;
 
        zTab = pTabList->a[j].zAlias;
        if( fullNames || zTab==0 ) zTab = pTab->zName;
        sqlite3SetString(&zName, zTab, ".", zCol, (char*)0);
        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, P3_DYNAMIC);
      }else{
        sqlite3VdbeSetColName(v, i, COLNAME_NAME, zCol, strlen(zCol));
      }
    }else if( p->span.z && p->span.z[0] ){
      sqlite3VdbeSetColName(v, i, COLNAME_NAME, (char*)p->span.z, p->span.n);
      /* sqlite3VdbeCompressSpace(v, addr); */
    }else{
      char zName[30];
      assert( p->op!=TK_COLUMN || pTabList==0 );
      sprintf(zName, "column%d", i+1);
      sqlite3VdbeSetColName(v, i, COLNAME_NAME, zName, 0);
    }
  }
  generateColumnTypes(pParse, pTabList, pEList);
}

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static void generateColumnTypes ( Parse pParse,
SrcList pTabList,
ExprList pEList 
) [static]

Definition at line 915 of file select.c.

 {
  Vdbe *v = pParse->pVdbe;
  int i;
  NameContext sNC;
  sNC.pSrcList = pTabList;
  sNC.pParse = pParse;
  for(i=0; i<pEList->nExpr; i++){
    Expr *p = pEList->a[i].pExpr;
    const char *zOrigDb = 0;
    const char *zOrigTab = 0;
    const char *zOrigCol = 0;
    const char *zType = columnType(&sNC, p, &zOrigDb, &zOrigTab, &zOrigCol);

    /* The vdbe must make it's own copy of the column-type and other 
    ** column specific strings, in case the schema is reset before this
    ** virtual machine is deleted.
    */
    sqlite3VdbeSetColName(v, i, COLNAME_DECLTYPE, zType, P3_TRANSIENT);
    sqlite3VdbeSetColName(v, i, COLNAME_DATABASE, zOrigDb, P3_TRANSIENT);
    sqlite3VdbeSetColName(v, i, COLNAME_TABLE, zOrigTab, P3_TRANSIENT);
    sqlite3VdbeSetColName(v, i, COLNAME_COLUMN, zOrigCol, P3_TRANSIENT);
  }
}

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static void generateSortTail ( Parse pParse,
Select p,
Vdbe v,
int  nColumn,
int  eDest,
int  iParm 
) [static]

Definition at line 679 of file select.c.

 {
  int brk = sqlite3VdbeMakeLabel(v);
  int cont = sqlite3VdbeMakeLabel(v);
  int addr;
  int iTab;
  int pseudoTab;
  ExprList *pOrderBy = p->pOrderBy;

  iTab = pOrderBy->iECursor;
  if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
    pseudoTab = pParse->nTab++;
    sqlite3VdbeAddOp(v, OP_OpenPseudo, pseudoTab, 0);
    sqlite3VdbeAddOp(v, OP_SetNumColumns, pseudoTab, nColumn);
  }
  addr = 1 + sqlite3VdbeAddOp(v, OP_Sort, iTab, brk);
  codeOffset(v, p, cont, 0);
  if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
    sqlite3VdbeAddOp(v, OP_Integer, 1, 0);
  }
  sqlite3VdbeAddOp(v, OP_Column, iTab, pOrderBy->nExpr + 1);
  switch( eDest ){
    case SRT_Table:
    case SRT_VirtualTab: {
      sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
      sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
      sqlite3VdbeAddOp(v, OP_Insert, iParm, 0);
      break;
    }
#ifndef SQLITE_OMIT_SUBQUERY
    case SRT_Set: {
      assert( nColumn==1 );
      sqlite3VdbeAddOp(v, OP_NotNull, -1, sqlite3VdbeCurrentAddr(v)+3);
      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
      sqlite3VdbeAddOp(v, OP_Goto, 0, sqlite3VdbeCurrentAddr(v)+3);
      sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, "c", P3_STATIC);
      sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
      break;
    }
    case SRT_Mem: {
      assert( nColumn==1 );
      sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }
#endif
    case SRT_Callback:
    case SRT_Subroutine: {
      int i;
      sqlite3VdbeAddOp(v, OP_Insert, pseudoTab, 0);
      for(i=0; i<nColumn; i++){
        sqlite3VdbeAddOp(v, OP_Column, pseudoTab, i);
      }
      if( eDest==SRT_Callback ){
        sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
      }else{
        sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
      }
      break;
    }
    default: {
      /* Do nothing */
      break;
    }
  }

  /* Jump to the end of the loop when the LIMIT is reached
  */
  if( p->iLimit>=0 ){
    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
    sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, brk);
  }

  /* The bottom of the loop
  */
  sqlite3VdbeResolveLabel(v, cont);
  sqlite3VdbeAddOp(v, OP_Next, iTab, addr);
  sqlite3VdbeResolveLabel(v, brk);
  if( eDest==SRT_Callback || eDest==SRT_Subroutine ){
    sqlite3VdbeAddOp(v, OP_Close, pseudoTab, 0);
  }

}

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static KeyInfo* keyInfoFromExprList ( Parse pParse,
ExprList pList 
) [static]

Definition at line 646 of file select.c.

                                                                   {
  sqlite3 *db = pParse->db;
  int nExpr;
  KeyInfo *pInfo;
  struct ExprList_item *pItem;
  int i;

  nExpr = pList->nExpr;
  pInfo = sqliteMalloc( sizeof(*pInfo) + nExpr*(sizeof(CollSeq*)+1) );
  if( pInfo ){
    pInfo->aSortOrder = (u8*)&pInfo->aColl[nExpr];
    pInfo->nField = nExpr;
    pInfo->enc = ENC(db);
    for(i=0, pItem=pList->a; i<nExpr; i++, pItem++){
      CollSeq *pColl;
      pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
      if( !pColl ){
        pColl = db->pDfltColl;
      }
      pInfo->aColl[i] = pColl;
      pInfo->aSortOrder[i] = pItem->sortOrder;
    }
  }
  return pInfo;
}

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static int matchOrderbyToColumn ( Parse pParse,
Select pSelect,
ExprList pOrderBy,
int  iTable,
int  mustComplete 
) [static]

Definition at line 1379 of file select.c.

 {
  int nErr = 0;
  int i, j;
  ExprList *pEList;

  if( pSelect==0 || pOrderBy==0 ) return 1;
  if( mustComplete ){
    for(i=0; i<pOrderBy->nExpr; i++){ pOrderBy->a[i].done = 0; }
  }
  if( prepSelectStmt(pParse, pSelect) ){
    return 1;
  }
  if( pSelect->pPrior ){
    if( matchOrderbyToColumn(pParse, pSelect->pPrior, pOrderBy, iTable, 0) ){
      return 1;
    }
  }
  pEList = pSelect->pEList;
  for(i=0; i<pOrderBy->nExpr; i++){
    Expr *pE = pOrderBy->a[i].pExpr;
    int iCol = -1;
    if( pOrderBy->a[i].done ) continue;
    if( sqlite3ExprIsInteger(pE, &iCol) ){
      if( iCol<=0 || iCol>pEList->nExpr ){
        sqlite3ErrorMsg(pParse,
          "ORDER BY position %d should be between 1 and %d",
          iCol, pEList->nExpr);
        nErr++;
        break;
      }
      if( !mustComplete ) continue;
      iCol--;
    }
    for(j=0; iCol<0 && j<pEList->nExpr; j++){
      if( pEList->a[j].zName && (pE->op==TK_ID || pE->op==TK_STRING) ){
        char *zName, *zLabel;
        zName = pEList->a[j].zName;
        zLabel = sqlite3NameFromToken(&pE->token);
        assert( zLabel!=0 );
        if( sqlite3StrICmp(zName, zLabel)==0 ){ 
          iCol = j;
        }
        sqliteFree(zLabel);
      }
      if( iCol<0 && sqlite3ExprCompare(pE, pEList->a[j].pExpr) ){
        iCol = j;
      }
    }
    if( iCol>=0 ){
      pE->op = TK_COLUMN;
      pE->iColumn = iCol;
      pE->iTable = iTable;
      pE->iAgg = -1;
      pOrderBy->a[i].done = 1;
    }
    if( iCol<0 && mustComplete ){
      sqlite3ErrorMsg(pParse,
        "ORDER BY term number %d does not match any result column", i+1);
      nErr++;
      break;
    }
  }
  return nErr;  
}

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static int multiSelect ( Parse pParse,
Select p,
int  eDest,
int  iParm,
char *  aff 
) [static]

Definition at line 1602 of file select.c.

 {
  int rc = SQLITE_OK;   /* Success code from a subroutine */
  Select *pPrior;       /* Another SELECT immediately to our left */
  Vdbe *v;              /* Generate code to this VDBE */
  int nCol;             /* Number of columns in the result set */
  ExprList *pOrderBy;   /* The ORDER BY clause on p */
  int aSetP2[2];        /* Set P2 value of these op to number of columns */
  int nSetP2 = 0;       /* Number of slots in aSetP2[] used */

  /* Make sure there is no ORDER BY or LIMIT clause on prior SELECTs.  Only
  ** the last (right-most) SELECT in the series may have an ORDER BY or LIMIT.
  */
  if( p==0 || p->pPrior==0 ){
    rc = 1;
    goto multi_select_end;
  }
  pPrior = p->pPrior;
  assert( pPrior->pRightmost!=pPrior );
  assert( pPrior->pRightmost==p->pRightmost );
  if( pPrior->pOrderBy ){
    sqlite3ErrorMsg(pParse,"ORDER BY clause should come after %s not before",
      selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }
  if( pPrior->pLimit ){
    sqlite3ErrorMsg(pParse,"LIMIT clause should come after %s not before",
      selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }

  /* Make sure we have a valid query engine.  If not, create a new one.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ){
    rc = 1;
    goto multi_select_end;
  }

  /* Create the destination temporary table if necessary
  */
  if( eDest==SRT_VirtualTab ){
    assert( p->pEList );
    assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
    aSetP2[nSetP2++] = sqlite3VdbeAddOp(v, OP_OpenVirtual, iParm, 0);
    eDest = SRT_Table;
  }

  /* Generate code for the left and right SELECT statements.
  */
  pOrderBy = p->pOrderBy;
  switch( p->op ){
    case TK_ALL: {
      if( pOrderBy==0 ){
        int addr = 0;
        assert( !pPrior->pLimit );
        pPrior->pLimit = p->pLimit;
        pPrior->pOffset = p->pOffset;
        rc = sqlite3Select(pParse, pPrior, eDest, iParm, 0, 0, 0, aff);
        p->pLimit = 0;
        p->pOffset = 0;
        if( rc ){
          goto multi_select_end;
        }
        p->pPrior = 0;
        p->iLimit = pPrior->iLimit;
        p->iOffset = pPrior->iOffset;
        if( p->iLimit>=0 ){
          addr = sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, 0);
          VdbeComment((v, "# Jump ahead if LIMIT reached"));
        }
        rc = sqlite3Select(pParse, p, eDest, iParm, 0, 0, 0, aff);
        p->pPrior = pPrior;
        if( rc ){
          goto multi_select_end;
        }
        if( addr ){
          sqlite3VdbeJumpHere(v, addr);
        }
        break;
      }
      /* For UNION ALL ... ORDER BY fall through to the next case */
    }
    case TK_EXCEPT:
    case TK_UNION: {
      int unionTab;    /* Cursor number of the temporary table holding result */
      int op = 0;      /* One of the SRT_ operations to apply to self */
      int priorOp;     /* The SRT_ operation to apply to prior selects */
      Expr *pLimit, *pOffset; /* Saved values of p->nLimit and p->nOffset */
      int addr;

      priorOp = p->op==TK_ALL ? SRT_Table : SRT_Union;
      if( eDest==priorOp && pOrderBy==0 && !p->pLimit && !p->pOffset ){
        /* We can reuse a temporary table generated by a SELECT to our
        ** right.
        */
        unionTab = iParm;
      }else{
        /* We will need to create our own temporary table to hold the
        ** intermediate results.
        */
        unionTab = pParse->nTab++;
        if( pOrderBy && matchOrderbyToColumn(pParse, p, pOrderBy, unionTab,1) ){
          rc = 1;
          goto multi_select_end;
        }
        addr = sqlite3VdbeAddOp(v, OP_OpenVirtual, unionTab, 0);
        if( priorOp==SRT_Table ){
          assert( nSetP2<sizeof(aSetP2)/sizeof(aSetP2[0]) );
          aSetP2[nSetP2++] = addr;
        }else{
          assert( p->addrOpenVirt[0] == -1 );
          p->addrOpenVirt[0] = addr;
          p->pRightmost->usesVirt = 1;
        }
        createSortingIndex(pParse, p, pOrderBy);
        assert( p->pEList );
      }

      /* Code the SELECT statements to our left
      */
      assert( !pPrior->pOrderBy );
      rc = sqlite3Select(pParse, pPrior, priorOp, unionTab, 0, 0, 0, aff);
      if( rc ){
        goto multi_select_end;
      }

      /* Code the current SELECT statement
      */
      switch( p->op ){
         case TK_EXCEPT:  op = SRT_Except;   break;
         case TK_UNION:   op = SRT_Union;    break;
         case TK_ALL:     op = SRT_Table;    break;
      }
      p->pPrior = 0;
      p->pOrderBy = 0;
      p->disallowOrderBy = pOrderBy!=0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      rc = sqlite3Select(pParse, p, op, unionTab, 0, 0, 0, aff);
      p->pPrior = pPrior;
      p->pOrderBy = pOrderBy;
      sqlite3ExprDelete(p->pLimit);
      p->pLimit = pLimit;
      p->pOffset = pOffset;
      p->iLimit = -1;
      p->iOffset = -1;
      if( rc ){
        goto multi_select_end;
      }


      /* Convert the data in the temporary table into whatever form
      ** it is that we currently need.
      */      
      if( eDest!=priorOp || unionTab!=iParm ){
        int iCont, iBreak, iStart;
        assert( p->pEList );
        if( eDest==SRT_Callback ){
          Select *pFirst = p;
          while( pFirst->pPrior ) pFirst = pFirst->pPrior;
          generateColumnNames(pParse, 0, pFirst->pEList);
        }
        iBreak = sqlite3VdbeMakeLabel(v);
        iCont = sqlite3VdbeMakeLabel(v);
        computeLimitRegisters(pParse, p, iBreak);
        sqlite3VdbeAddOp(v, OP_Rewind, unionTab, iBreak);
        iStart = sqlite3VdbeCurrentAddr(v);
        rc = selectInnerLoop(pParse, p, p->pEList, unionTab, p->pEList->nExpr,
                             pOrderBy, -1, eDest, iParm, 
                             iCont, iBreak, 0);
        if( rc ){
          rc = 1;
          goto multi_select_end;
        }
        sqlite3VdbeResolveLabel(v, iCont);
        sqlite3VdbeAddOp(v, OP_Next, unionTab, iStart);
        sqlite3VdbeResolveLabel(v, iBreak);
        sqlite3VdbeAddOp(v, OP_Close, unionTab, 0);
      }
      break;
    }
    case TK_INTERSECT: {
      int tab1, tab2;
      int iCont, iBreak, iStart;
      Expr *pLimit, *pOffset;
      int addr;

      /* INTERSECT is different from the others since it requires
      ** two temporary tables.  Hence it has its own case.  Begin
      ** by allocating the tables we will need.
      */
      tab1 = pParse->nTab++;
      tab2 = pParse->nTab++;
      if( pOrderBy && matchOrderbyToColumn(pParse,p,pOrderBy,tab1,1) ){
        rc = 1;
        goto multi_select_end;
      }
      createSortingIndex(pParse, p, pOrderBy);

      addr = sqlite3VdbeAddOp(v, OP_OpenVirtual, tab1, 0);
      assert( p->addrOpenVirt[0] == -1 );
      p->addrOpenVirt[0] = addr;
      p->pRightmost->usesVirt = 1;
      assert( p->pEList );

      /* Code the SELECTs to our left into temporary table "tab1".
      */
      rc = sqlite3Select(pParse, pPrior, SRT_Union, tab1, 0, 0, 0, aff);
      if( rc ){
        goto multi_select_end;
      }

      /* Code the current SELECT into temporary table "tab2"
      */
      addr = sqlite3VdbeAddOp(v, OP_OpenVirtual, tab2, 0);
      assert( p->addrOpenVirt[1] == -1 );
      p->addrOpenVirt[1] = addr;
      p->pPrior = 0;
      pLimit = p->pLimit;
      p->pLimit = 0;
      pOffset = p->pOffset;
      p->pOffset = 0;
      rc = sqlite3Select(pParse, p, SRT_Union, tab2, 0, 0, 0, aff);
      p->pPrior = pPrior;
      sqlite3ExprDelete(p->pLimit);
      p->pLimit = pLimit;
      p->pOffset = pOffset;
      if( rc ){
        goto multi_select_end;
      }

      /* Generate code to take the intersection of the two temporary
      ** tables.
      */
      assert( p->pEList );
      if( eDest==SRT_Callback ){
        Select *pFirst = p;
        while( pFirst->pPrior ) pFirst = pFirst->pPrior;
        generateColumnNames(pParse, 0, pFirst->pEList);
      }
      iBreak = sqlite3VdbeMakeLabel(v);
      iCont = sqlite3VdbeMakeLabel(v);
      computeLimitRegisters(pParse, p, iBreak);
      sqlite3VdbeAddOp(v, OP_Rewind, tab1, iBreak);
      iStart = sqlite3VdbeAddOp(v, OP_RowKey, tab1, 0);
      sqlite3VdbeAddOp(v, OP_NotFound, tab2, iCont);
      rc = selectInnerLoop(pParse, p, p->pEList, tab1, p->pEList->nExpr,
                             pOrderBy, -1, eDest, iParm, 
                             iCont, iBreak, 0);
      if( rc ){
        rc = 1;
        goto multi_select_end;
      }
      sqlite3VdbeResolveLabel(v, iCont);
      sqlite3VdbeAddOp(v, OP_Next, tab1, iStart);
      sqlite3VdbeResolveLabel(v, iBreak);
      sqlite3VdbeAddOp(v, OP_Close, tab2, 0);
      sqlite3VdbeAddOp(v, OP_Close, tab1, 0);
      break;
    }
  }

  /* Make sure all SELECTs in the statement have the same number of elements
  ** in their result sets.
  */
  assert( p->pEList && pPrior->pEList );
  if( p->pEList->nExpr!=pPrior->pEList->nExpr ){
    sqlite3ErrorMsg(pParse, "SELECTs to the left and right of %s"
      " do not have the same number of result columns", selectOpName(p->op));
    rc = 1;
    goto multi_select_end;
  }

  /* Set the number of columns in temporary tables
  */
  nCol = p->pEList->nExpr;
  while( nSetP2 ){
    sqlite3VdbeChangeP2(v, aSetP2[--nSetP2], nCol);
  }

  /* Compute collating sequences used by either the ORDER BY clause or
  ** by any temporary tables needed to implement the compound select.
  ** Attach the KeyInfo structure to all temporary tables.  Invoke the
  ** ORDER BY processing if there is an ORDER BY clause.
  **
  ** This section is run by the right-most SELECT statement only.
  ** SELECT statements to the left always skip this part.  The right-most
  ** SELECT might also skip this part if it has no ORDER BY clause and
  ** no temp tables are required.
  */
  if( pOrderBy || p->usesVirt ){
    int i;                        /* Loop counter */
    KeyInfo *pKeyInfo;            /* Collating sequence for the result set */
    Select *pLoop;                /* For looping through SELECT statements */
    CollSeq **apColl;
    CollSeq **aCopy;

    assert( p->pRightmost==p );
    pKeyInfo = sqliteMalloc(sizeof(*pKeyInfo)+nCol*2*sizeof(CollSeq*) + nCol);
    if( !pKeyInfo ){
      rc = SQLITE_NOMEM;
      goto multi_select_end;
    }

    pKeyInfo->enc = ENC(pParse->db);
    pKeyInfo->nField = nCol;

    for(i=0, apColl=pKeyInfo->aColl; i<nCol; i++, apColl++){
      *apColl = multiSelectCollSeq(pParse, p, i);
      if( 0==*apColl ){
        *apColl = pParse->db->pDfltColl;
      }
    }

    for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
      for(i=0; i<2; i++){
        int addr = pLoop->addrOpenVirt[i];
        if( addr<0 ){
          /* If [0] is unused then [1] is also unused.  So we can
          ** always safely abort as soon as the first unused slot is found */
          assert( pLoop->addrOpenVirt[1]<0 );
          break;
        }
        sqlite3VdbeChangeP2(v, addr, nCol);
        sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO);
      }
    }

    if( pOrderBy ){
      struct ExprList_item *pOTerm = pOrderBy->a;
      int nOrderByExpr = pOrderBy->nExpr;
      int addr;
      u8 *pSortOrder;

      aCopy = &pKeyInfo->aColl[nCol];
      pSortOrder = pKeyInfo->aSortOrder = (u8*)&aCopy[nCol];
      memcpy(aCopy, pKeyInfo->aColl, nCol*sizeof(CollSeq*));
      apColl = pKeyInfo->aColl;
      for(i=0; i<nOrderByExpr; i++, pOTerm++, apColl++, pSortOrder++){
        Expr *pExpr = pOTerm->pExpr;
        char *zName = pOTerm->zName;
        assert( pExpr->op==TK_COLUMN && pExpr->iColumn<nCol );
        if( zName ){
          *apColl = sqlite3LocateCollSeq(pParse, zName, -1);
        }else{
          *apColl = aCopy[pExpr->iColumn];
        }
        *pSortOrder = pOTerm->sortOrder;
      }
      assert( p->pRightmost==p );
      assert( p->addrOpenVirt[2]>=0 );
      addr = p->addrOpenVirt[2];
      sqlite3VdbeChangeP2(v, addr, p->pEList->nExpr+2);
      pKeyInfo->nField = nOrderByExpr;
      sqlite3VdbeChangeP3(v, addr, (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
      pKeyInfo = 0;
      generateSortTail(pParse, p, v, p->pEList->nExpr, eDest, iParm);
    }

    sqliteFree(pKeyInfo);
  }

multi_select_end:
  return rc;
}

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static CollSeq* multiSelectCollSeq ( Parse pParse,
Select p,
int  iCol 
) [static]

Definition at line 1557 of file select.c.

                                                                      {
  CollSeq *pRet;
  if( p->pPrior ){
    pRet = multiSelectCollSeq(pParse, p->pPrior, iCol);
  }else{
    pRet = 0;
  }
  if( pRet==0 ){
    pRet = sqlite3ExprCollSeq(pParse, p->pEList->a[iCol].pExpr);
  }
  return pRet;
}

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static int prepSelectStmt ( Parse pParse,
Select p 
) [static]

Definition at line 1161 of file select.c.

                                                   {
  int i, j, k, rc;
  SrcList *pTabList;
  ExprList *pEList;
  struct SrcList_item *pFrom;

  if( p==0 || p->pSrc==0 || sqlite3MallocFailed() ){
    return 1;
  }
  pTabList = p->pSrc;
  pEList = p->pEList;

  /* Make sure cursor numbers have been assigned to all entries in
  ** the FROM clause of the SELECT statement.
  */
  sqlite3SrcListAssignCursors(pParse, p->pSrc);

  /* Look up every table named in the FROM clause of the select.  If
  ** an entry of the FROM clause is a subquery instead of a table or view,
  ** then create a transient table structure to describe the subquery.
  */
  for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
    Table *pTab;
    if( pFrom->pTab!=0 ){
      /* This statement has already been prepared.  There is no need
      ** to go further. */
      assert( i==0 );
      return 0;
    }
    if( pFrom->zName==0 ){
#ifndef SQLITE_OMIT_SUBQUERY
      /* A sub-query in the FROM clause of a SELECT */
      assert( pFrom->pSelect!=0 );
      if( pFrom->zAlias==0 ){
        pFrom->zAlias =
          sqlite3MPrintf("sqlite_subquery_%p_", (void*)pFrom->pSelect);
      }
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3ResultSetOfSelect(pParse, pFrom->zAlias, pFrom->pSelect);
      if( pTab==0 ){
        return 1;
      }
      /* The isTransient flag indicates that the Table structure has been
      ** dynamically allocated and may be freed at any time.  In other words,
      ** pTab is not pointing to a persistent table structure that defines
      ** part of the schema. */
      pTab->isTransient = 1;
#endif
    }else{
      /* An ordinary table or view name in the FROM clause */
      assert( pFrom->pTab==0 );
      pFrom->pTab = pTab = 
        sqlite3LocateTable(pParse,pFrom->zName,pFrom->zDatabase);
      if( pTab==0 ){
        return 1;
      }
      pTab->nRef++;
#ifndef SQLITE_OMIT_VIEW
      if( pTab->pSelect ){
        /* We reach here if the named table is a really a view */
        if( sqlite3ViewGetColumnNames(pParse, pTab) ){
          return 1;
        }
        /* If pFrom->pSelect!=0 it means we are dealing with a
        ** view within a view.  The SELECT structure has already been
        ** copied by the outer view so we can skip the copy step here
        ** in the inner view.
        */
        if( pFrom->pSelect==0 ){
          pFrom->pSelect = sqlite3SelectDup(pTab->pSelect);
        }
      }
#endif
    }
  }

  /* Process NATURAL keywords, and ON and USING clauses of joins.
  */
  if( sqliteProcessJoin(pParse, p) ) return 1;

  /* For every "*" that occurs in the column list, insert the names of
  ** all columns in all tables.  And for every TABLE.* insert the names
  ** of all columns in TABLE.  The parser inserted a special expression
  ** with the TK_ALL operator for each "*" that it found in the column list.
  ** The following code just has to locate the TK_ALL expressions and expand
  ** each one to the list of all columns in all tables.
  **
  ** The first loop just checks to see if there are any "*" operators
  ** that need expanding.
  */
  for(k=0; k<pEList->nExpr; k++){
    Expr *pE = pEList->a[k].pExpr;
    if( pE->op==TK_ALL ) break;
    if( pE->op==TK_DOT && pE->pRight && pE->pRight->op==TK_ALL
         && pE->pLeft && pE->pLeft->op==TK_ID ) break;
  }
  rc = 0;
  if( k<pEList->nExpr ){
    /*
    ** If we get here it means the result set contains one or more "*"
    ** operators that need to be expanded.  Loop through each expression
    ** in the result set and expand them one by one.
    */
    struct ExprList_item *a = pEList->a;
    ExprList *pNew = 0;
    int flags = pParse->db->flags;
    int longNames = (flags & SQLITE_FullColNames)!=0 &&
                      (flags & SQLITE_ShortColNames)==0;

    for(k=0; k<pEList->nExpr; k++){
      Expr *pE = a[k].pExpr;
      if( pE->op!=TK_ALL &&
           (pE->op!=TK_DOT || pE->pRight==0 || pE->pRight->op!=TK_ALL) ){
        /* This particular expression does not need to be expanded.
        */
        pNew = sqlite3ExprListAppend(pNew, a[k].pExpr, 0);
        if( pNew ){
          pNew->a[pNew->nExpr-1].zName = a[k].zName;
        }else{
          rc = 1;
        }
        a[k].pExpr = 0;
        a[k].zName = 0;
      }else{
        /* This expression is a "*" or a "TABLE.*" and needs to be
        ** expanded. */
        int tableSeen = 0;      /* Set to 1 when TABLE matches */
        char *zTName;            /* text of name of TABLE */
        if( pE->op==TK_DOT && pE->pLeft ){
          zTName = sqlite3NameFromToken(&pE->pLeft->token);
        }else{
          zTName = 0;
        }
        for(i=0, pFrom=pTabList->a; i<pTabList->nSrc; i++, pFrom++){
          Table *pTab = pFrom->pTab;
          char *zTabName = pFrom->zAlias;
          if( zTabName==0 || zTabName[0]==0 ){ 
            zTabName = pTab->zName;
          }
          if( zTName && (zTabName==0 || zTabName[0]==0 || 
                 sqlite3StrICmp(zTName, zTabName)!=0) ){
            continue;
          }
          tableSeen = 1;
          for(j=0; j<pTab->nCol; j++){
            Expr *pExpr, *pRight;
            char *zName = pTab->aCol[j].zName;

            if( i>0 ){
              struct SrcList_item *pLeft = &pTabList->a[i-1];
              if( (pLeft->jointype & JT_NATURAL)!=0 &&
                        columnIndex(pLeft->pTab, zName)>=0 ){
                /* In a NATURAL join, omit the join columns from the 
                ** table on the right */
                continue;
              }
              if( sqlite3IdListIndex(pLeft->pUsing, zName)>=0 ){
                /* In a join with a USING clause, omit columns in the
                ** using clause from the table on the right. */
                continue;
              }
            }
            pRight = sqlite3Expr(TK_ID, 0, 0, 0);
            if( pRight==0 ) break;
            setToken(&pRight->token, zName);
            if( zTabName && (longNames || pTabList->nSrc>1) ){
              Expr *pLeft = sqlite3Expr(TK_ID, 0, 0, 0);
              pExpr = sqlite3Expr(TK_DOT, pLeft, pRight, 0);
              if( pExpr==0 ) break;
              setToken(&pLeft->token, zTabName);
              setToken(&pExpr->span, sqlite3MPrintf("%s.%s", zTabName, zName));
              pExpr->span.dyn = 1;
              pExpr->token.z = 0;
              pExpr->token.n = 0;
              pExpr->token.dyn = 0;
            }else{
              pExpr = pRight;
              pExpr->span = pExpr->token;
            }
            if( longNames ){
              pNew = sqlite3ExprListAppend(pNew, pExpr, &pExpr->span);
            }else{
              pNew = sqlite3ExprListAppend(pNew, pExpr, &pRight->token);
            }
          }
        }
        if( !tableSeen ){
          if( zTName ){
            sqlite3ErrorMsg(pParse, "no such table: %s", zTName);
          }else{
            sqlite3ErrorMsg(pParse, "no tables specified");
          }
          rc = 1;
        }
        sqliteFree(zTName);
      }
    }
    sqlite3ExprListDelete(pEList);
    p->pEList = pNew;
  }
  return rc;
}

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static int processOrderGroupBy ( NameContext pNC,
ExprList pOrderBy,
const char *  zType 
) [static]

Definition at line 2461 of file select.c.

 {
  int i;
  ExprList *pEList = pNC->pEList;     /* The result set of the SELECT */
  Parse *pParse = pNC->pParse;     /* The result set of the SELECT */
  assert( pEList );

  if( pOrderBy==0 ) return 0;
  for(i=0; i<pOrderBy->nExpr; i++){
    int iCol;
    Expr *pE = pOrderBy->a[i].pExpr;
    if( sqlite3ExprIsInteger(pE, &iCol) ){
      if( iCol>0 && iCol<=pEList->nExpr ){
        sqlite3ExprDelete(pE);
        pE = pOrderBy->a[i].pExpr = sqlite3ExprDup(pEList->a[iCol-1].pExpr);
      }else{
        sqlite3ErrorMsg(pParse, 
           "%s BY column number %d out of range - should be "
           "between 1 and %d", zType, iCol, pEList->nExpr);
        return 1;
      }
    }
    if( sqlite3ExprResolveNames(pNC, pE) ){
      return 1;
    }
  }
  return 0;
}

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static void pushOntoSorter ( Parse pParse,
ExprList pOrderBy,
Select pSelect 
) [static]

Definition at line 362 of file select.c.

 {
  Vdbe *v = pParse->pVdbe;
  sqlite3ExprCodeExprList(pParse, pOrderBy);
  sqlite3VdbeAddOp(v, OP_Sequence, pOrderBy->iECursor, 0);
  sqlite3VdbeAddOp(v, OP_Pull, pOrderBy->nExpr + 1, 0);
  sqlite3VdbeAddOp(v, OP_MakeRecord, pOrderBy->nExpr + 2, 0);
  sqlite3VdbeAddOp(v, OP_IdxInsert, pOrderBy->iECursor, 0);
  if( pSelect->iLimit>=0 ){
    int addr1, addr2;
    addr1 = sqlite3VdbeAddOp(v, OP_IfMemZero, pSelect->iLimit+1, 0);
    sqlite3VdbeAddOp(v, OP_MemIncr, -1, pSelect->iLimit+1);
    addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
    sqlite3VdbeJumpHere(v, addr1);
    sqlite3VdbeAddOp(v, OP_Last, pOrderBy->iECursor, 0);
    sqlite3VdbeAddOp(v, OP_Delete, pOrderBy->iECursor, 0);
    sqlite3VdbeJumpHere(v, addr2);
    pSelect->iLimit = -1;
  }
}

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static void resetAccumulator ( Parse pParse,
AggInfo pAggInfo 
) [static]

Definition at line 2614 of file select.c.

                                                              {
  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pFunc;
  if( pAggInfo->nFunc+pAggInfo->nColumn==0 ){
    return;
  }
  for(i=0; i<pAggInfo->nColumn; i++){
    sqlite3VdbeAddOp(v, OP_MemNull, pAggInfo->aCol[i].iMem, 0);
  }
  for(pFunc=pAggInfo->aFunc, i=0; i<pAggInfo->nFunc; i++, pFunc++){
    sqlite3VdbeAddOp(v, OP_MemNull, pFunc->iMem, 0);
    if( pFunc->iDistinct>=0 ){
      Expr *pE = pFunc->pExpr;
      if( pE->pList==0 || pE->pList->nExpr!=1 ){
        sqlite3ErrorMsg(pParse, "DISTINCT in aggregate must be followed "
           "by an expression");
        pFunc->iDistinct = -1;
      }else{
        KeyInfo *pKeyInfo = keyInfoFromExprList(pParse, pE->pList);
        sqlite3VdbeOp3(v, OP_OpenVirtual, pFunc->iDistinct, 0, 
                          (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
      }
    }
  }
}

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static int selectInnerLoop ( Parse pParse,
Select p,
ExprList pEList,
int  srcTab,
int  nColumn,
ExprList pOrderBy,
int  distinct,
int  eDest,
int  iParm,
int  iContinue,
int  iBreak,
char *  aff 
) [static]

Definition at line 441 of file select.c.

 {
  Vdbe *v = pParse->pVdbe;
  int i;
  int hasDistinct;        /* True if the DISTINCT keyword is present */

  if( v==0 ) return 0;
  assert( pEList!=0 );

  /* If there was a LIMIT clause on the SELECT statement, then do the check
  ** to see if this row should be output.
  */
  hasDistinct = distinct>=0 && pEList->nExpr>0;
  if( pOrderBy==0 && !hasDistinct ){
    codeOffset(v, p, iContinue, 0);
  }

  /* Pull the requested columns.
  */
  if( nColumn>0 ){
    for(i=0; i<nColumn; i++){
      sqlite3VdbeAddOp(v, OP_Column, srcTab, i);
    }
  }else{
    nColumn = pEList->nExpr;
    sqlite3ExprCodeExprList(pParse, pEList);
  }

  /* If the DISTINCT keyword was present on the SELECT statement
  ** and this row has been seen before, then do not make this row
  ** part of the result.
  */
  if( hasDistinct ){
    assert( pEList!=0 );
    assert( pEList->nExpr==nColumn );
    codeDistinct(v, distinct, iContinue, nColumn);
    if( pOrderBy==0 ){
      codeOffset(v, p, iContinue, nColumn);
    }
  }

  switch( eDest ){
    /* In this mode, write each query result to the key of the temporary
    ** table iParm.
    */
#ifndef SQLITE_OMIT_COMPOUND_SELECT
    case SRT_Union: {
      sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
      if( aff ){
        sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
      }
      sqlite3VdbeAddOp(v, OP_IdxInsert, iParm, 0);
      break;
    }

    /* Construct a record from the query result, but instead of
    ** saving that record, use it as a key to delete elements from
    ** the temporary table iParm.
    */
    case SRT_Except: {
      int addr;
      addr = sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
      sqlite3VdbeChangeP3(v, -1, aff, P3_STATIC);
      sqlite3VdbeAddOp(v, OP_NotFound, iParm, addr+3);
      sqlite3VdbeAddOp(v, OP_Delete, iParm, 0);
      break;
    }
#endif

    /* Store the result as data using a unique key.
    */
    case SRT_Table:
    case SRT_VirtualTab: {
      sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p);
      }else{
        sqlite3VdbeAddOp(v, OP_NewRowid, iParm, 0);
        sqlite3VdbeAddOp(v, OP_Pull, 1, 0);
        sqlite3VdbeAddOp(v, OP_Insert, iParm, 0);
      }
      break;
    }

#ifndef SQLITE_OMIT_SUBQUERY
    /* If we are creating a set for an "expr IN (SELECT ...)" construct,
    ** then there should be a single item on the stack.  Write this
    ** item into the set table with bogus data.
    */
    case SRT_Set: {
      int addr1 = sqlite3VdbeCurrentAddr(v);
      int addr2;

      assert( nColumn==1 );
      sqlite3VdbeAddOp(v, OP_NotNull, -1, addr1+3);
      sqlite3VdbeAddOp(v, OP_Pop, 1, 0);
      addr2 = sqlite3VdbeAddOp(v, OP_Goto, 0, 0);
      if( pOrderBy ){
        /* At first glance you would think we could optimize out the
        ** ORDER BY in this case since the order of entries in the set
        ** does not matter.  But there might be a LIMIT clause, in which
        ** case the order does matter */
        pushOntoSorter(pParse, pOrderBy, p);
      }else{
        char affinity = (iParm>>16)&0xFF;
        affinity = sqlite3CompareAffinity(pEList->a[0].pExpr, affinity);
        sqlite3VdbeOp3(v, OP_MakeRecord, 1, 0, &affinity, 1);
        sqlite3VdbeAddOp(v, OP_IdxInsert, (iParm&0x0000FFFF), 0);
      }
      sqlite3VdbeJumpHere(v, addr2);
      break;
    }

    /* If any row exist in the result set, record that fact and abort.
    */
    case SRT_Exists: {
      sqlite3VdbeAddOp(v, OP_MemInt, 1, iParm);
      sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
      /* The LIMIT clause will terminate the loop for us */
      break;
    }

    /* If this is a scalar select that is part of an expression, then
    ** store the results in the appropriate memory cell and break out
    ** of the scan loop.
    */
    case SRT_Mem: {
      assert( nColumn==1 );
      if( pOrderBy ){
        pushOntoSorter(pParse, pOrderBy, p);
      }else{
        sqlite3VdbeAddOp(v, OP_MemStore, iParm, 1);
        /* The LIMIT clause will jump out of the loop for us */
      }
      break;
    }
#endif /* #ifndef SQLITE_OMIT_SUBQUERY */

    /* Send the data to the callback function or to a subroutine.  In the
    ** case of a subroutine, the subroutine itself is responsible for
    ** popping the data from the stack.
    */
    case SRT_Subroutine:
    case SRT_Callback: {
      if( pOrderBy ){
        sqlite3VdbeAddOp(v, OP_MakeRecord, nColumn, 0);
        pushOntoSorter(pParse, pOrderBy, p);
      }else if( eDest==SRT_Subroutine ){
        sqlite3VdbeAddOp(v, OP_Gosub, 0, iParm);
      }else{
        sqlite3VdbeAddOp(v, OP_Callback, nColumn, 0);
      }
      break;
    }

#if !defined(SQLITE_OMIT_TRIGGER)
    /* Discard the results.  This is used for SELECT statements inside
    ** the body of a TRIGGER.  The purpose of such selects is to call
    ** user-defined functions that have side effects.  We do not care
    ** about the actual results of the select.
    */
    default: {
      assert( eDest==SRT_Discard );
      sqlite3VdbeAddOp(v, OP_Pop, nColumn, 0);
      break;
    }
#endif
  }

  /* Jump to the end of the loop if the LIMIT is reached.
  */
  if( p->iLimit>=0 && pOrderBy==0 ){
    sqlite3VdbeAddOp(v, OP_MemIncr, -1, p->iLimit);
    sqlite3VdbeAddOp(v, OP_IfMemZero, p->iLimit, iBreak);
  }
  return 0;
}

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static const char* selectOpName ( int  id) [static]

Definition at line 1024 of file select.c.

                                       {
  char *z;
  switch( id ){
    case TK_ALL:       z = "UNION ALL";   break;
    case TK_INTERSECT: z = "INTERSECT";   break;
    case TK_EXCEPT:    z = "EXCEPT";      break;
    default:           z = "UNION";       break;
  }
  return z;
}

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static void setJoinExpr ( Expr p,
int  iTable 
) [static]

Definition at line 258 of file select.c.

                                            {
  while( p ){
    ExprSetProperty(p, EP_FromJoin);
    p->iRightJoinTable = iTable;
    setJoinExpr(p->pLeft, iTable);
    p = p->pRight;
  } 
}

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static void setToken ( Token p,
const char *  z 
) [static]

Definition at line 181 of file select.c.

                                             {
  p->z = (u8*)z;
  p->n = z ? strlen(z) : 0;
  p->dyn = 0;
}

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static int simpleMinMaxQuery ( Parse pParse,
Select p,
int  eDest,
int  iParm 
) [static]

Definition at line 2328 of file select.c.

                                                                            {
  Expr *pExpr;
  int iCol;
  Table *pTab;
  Index *pIdx;
  int base;
  Vdbe *v;
  int seekOp;
  ExprList *pEList, *pList, eList;
  struct ExprList_item eListItem;
  SrcList *pSrc;
  int brk;
  int iDb;

  /* Check to see if this query is a simple min() or max() query.  Return
  ** zero if it is  not.
  */
  if( p->pGroupBy || p->pHaving || p->pWhere ) return 0;
  pSrc = p->pSrc;
  if( pSrc->nSrc!=1 ) return 0;
  pEList = p->pEList;
  if( pEList->nExpr!=1 ) return 0;
  pExpr = pEList->a[0].pExpr;
  if( pExpr->op!=TK_AGG_FUNCTION ) return 0;
  pList = pExpr->pList;
  if( pList==0 || pList->nExpr!=1 ) return 0;
  if( pExpr->token.n!=3 ) return 0;
  if( sqlite3StrNICmp((char*)pExpr->token.z,"min",3)==0 ){
    seekOp = OP_Rewind;
  }else if( sqlite3StrNICmp((char*)pExpr->token.z,"max",3)==0 ){
    seekOp = OP_Last;
  }else{
    return 0;
  }
  pExpr = pList->a[0].pExpr;
  if( pExpr->op!=TK_COLUMN ) return 0;
  iCol = pExpr->iColumn;
  pTab = pSrc->a[0].pTab;


  /* If we get to here, it means the query is of the correct form.
  ** Check to make sure we have an index and make pIdx point to the
  ** appropriate index.  If the min() or max() is on an INTEGER PRIMARY
  ** key column, no index is necessary so set pIdx to NULL.  If no
  ** usable index is found, return 0.
  */
  if( iCol<0 ){
    pIdx = 0;
  }else{
    CollSeq *pColl = sqlite3ExprCollSeq(pParse, pExpr);
    for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
      assert( pIdx->nColumn>=1 );
      if( pIdx->aiColumn[0]==iCol && 
          0==sqlite3StrICmp(pIdx->azColl[0], pColl->zName) ){
        break;
      }
    }
    if( pIdx==0 ) return 0;
  }

  /* Identify column types if we will be using the callback.  This
  ** step is skipped if the output is going to a table or a memory cell.
  ** The column names have already been generated in the calling function.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) return 0;

  /* If the output is destined for a temporary table, open that table.
  */
  if( eDest==SRT_VirtualTab ){
    sqlite3VdbeAddOp(v, OP_OpenVirtual, iParm, 1);
  }

  /* Generating code to find the min or the max.  Basically all we have
  ** to do is find the first or the last entry in the chosen index.  If
  ** the min() or max() is on the INTEGER PRIMARY KEY, then find the first
  ** or last entry in the main table.
  */
  iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  assert( iDb>=0 || pTab->isTransient );
  sqlite3CodeVerifySchema(pParse, iDb);
  sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
  base = pSrc->a[0].iCursor;
  brk = sqlite3VdbeMakeLabel(v);
  computeLimitRegisters(pParse, p, brk);
  if( pSrc->a[0].pSelect==0 ){
    sqlite3OpenTable(pParse, base, iDb, pTab, OP_OpenRead);
  }
  if( pIdx==0 ){
    sqlite3VdbeAddOp(v, seekOp, base, 0);
  }else{
    /* Even though the cursor used to open the index here is closed
    ** as soon as a single value has been read from it, allocate it
    ** using (pParse->nTab++) to prevent the cursor id from being 
    ** reused. This is important for statements of the form 
    ** "INSERT INTO x SELECT max() FROM x".
    */
    int iIdx;
    KeyInfo *pKey = sqlite3IndexKeyinfo(pParse, pIdx);
    iIdx = pParse->nTab++;
    assert( pIdx->pSchema==pTab->pSchema );
    sqlite3VdbeAddOp(v, OP_Integer, iDb, 0);
    sqlite3VdbeOp3(v, OP_OpenRead, iIdx, pIdx->tnum, 
        (char*)pKey, P3_KEYINFO_HANDOFF);
    if( seekOp==OP_Rewind ){
      sqlite3VdbeAddOp(v, OP_Null, 0, 0);
      sqlite3VdbeAddOp(v, OP_MakeRecord, 1, 0);
      seekOp = OP_MoveGt;
    }
    sqlite3VdbeAddOp(v, seekOp, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_IdxRowid, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_Close, iIdx, 0);
    sqlite3VdbeAddOp(v, OP_MoveGe, base, 0);
  }
  eList.nExpr = 1;
  memset(&eListItem, 0, sizeof(eListItem));
  eList.a = &eListItem;
  eList.a[0].pExpr = pExpr;
  selectInnerLoop(pParse, p, &eList, 0, 0, 0, -1, eDest, iParm, brk, brk, 0);
  sqlite3VdbeResolveLabel(v, brk);
  sqlite3VdbeAddOp(v, OP_Close, base, 0);
  
  return 1;
}

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Vdbe* sqlite3GetVdbe ( Parse pParse)

Definition at line 1455 of file select.c.

                                   {
  Vdbe *v = pParse->pVdbe;
  if( v==0 ){
    v = pParse->pVdbe = sqlite3VdbeCreate(pParse->db);
  }
  return v;
}

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int sqlite3JoinType ( Parse pParse,
Token pA,
Token pB,
Token pC 
)

Definition at line 112 of file select.c.

                                                                   {
  int jointype = 0;
  Token *apAll[3];
  Token *p;
  static const struct {
    const char zKeyword[8];
    u8 nChar;
    u8 code;
  } keywords[] = {
    { "natural", 7, JT_NATURAL },
    { "left",    4, JT_LEFT|JT_OUTER },
    { "right",   5, JT_RIGHT|JT_OUTER },
    { "full",    4, JT_LEFT|JT_RIGHT|JT_OUTER },
    { "outer",   5, JT_OUTER },
    { "inner",   5, JT_INNER },
    { "cross",   5, JT_INNER|JT_CROSS },
  };
  int i, j;
  apAll[0] = pA;
  apAll[1] = pB;
  apAll[2] = pC;
  for(i=0; i<3 && apAll[i]; i++){
    p = apAll[i];
    for(j=0; j<sizeof(keywords)/sizeof(keywords[0]); j++){
      if( p->n==keywords[j].nChar 
          && sqlite3StrNICmp((char*)p->z, keywords[j].zKeyword, p->n)==0 ){
        jointype |= keywords[j].code;
        break;
      }
    }
    if( j>=sizeof(keywords)/sizeof(keywords[0]) ){
      jointype |= JT_ERROR;
      break;
    }
  }
  if(
     (jointype & (JT_INNER|JT_OUTER))==(JT_INNER|JT_OUTER) ||
     (jointype & JT_ERROR)!=0
  ){
    const char *zSp1 = " ";
    const char *zSp2 = " ";
    if( pB==0 ){ zSp1++; }
    if( pC==0 ){ zSp2++; }
    sqlite3ErrorMsg(pParse, "unknown or unsupported join type: "
       "%T%s%T%s%T", pA, zSp1, pB, zSp2, pC);
    jointype = JT_INNER;
  }else if( jointype & JT_RIGHT ){
    sqlite3ErrorMsg(pParse, 
      "RIGHT and FULL OUTER JOINs are not currently supported");
    jointype = JT_INNER;
  }
  return jointype;
}

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Table* sqlite3ResultSetOfSelect ( Parse pParse,
char *  zTabName,
Select pSelect 
)

Definition at line 1045 of file select.c.

                                                                               {
  Table *pTab;
  int i, j;
  ExprList *pEList;
  Column *aCol, *pCol;

  while( pSelect->pPrior ) pSelect = pSelect->pPrior;
  if( prepSelectStmt(pParse, pSelect) ){
    return 0;
  }
  if( sqlite3SelectResolve(pParse, pSelect, 0) ){
    return 0;
  }
  pTab = sqliteMalloc( sizeof(Table) );
  if( pTab==0 ){
    return 0;
  }
  pTab->nRef = 1;
  pTab->zName = zTabName ? sqliteStrDup(zTabName) : 0;
  pEList = pSelect->pEList;
  pTab->nCol = pEList->nExpr;
  assert( pTab->nCol>0 );
  pTab->aCol = aCol = sqliteMalloc( sizeof(pTab->aCol[0])*pTab->nCol );
  for(i=0, pCol=aCol; i<pTab->nCol; i++, pCol++){
    Expr *p, *pR;
    char *zType;
    char *zName;
    char *zBasename;
    CollSeq *pColl;
    int cnt;
    NameContext sNC;
    
    /* Get an appropriate name for the column
    */
    p = pEList->a[i].pExpr;
    assert( p->pRight==0 || p->pRight->token.z==0 || p->pRight->token.z[0]!=0 );
    if( (zName = pEList->a[i].zName)!=0 ){
      /* If the column contains an "AS <name>" phrase, use <name> as the name */
      zName = sqliteStrDup(zName);
    }else if( p->op==TK_DOT 
              && (pR=p->pRight)!=0 && pR->token.z && pR->token.z[0] ){
      /* For columns of the from A.B use B as the name */
      zName = sqlite3MPrintf("%T", &pR->token);
    }else if( p->span.z && p->span.z[0] ){
      /* Use the original text of the column expression as its name */
      zName = sqlite3MPrintf("%T", &p->span);
    }else{
      /* If all else fails, make up a name */
      zName = sqlite3MPrintf("column%d", i+1);
    }
    sqlite3Dequote(zName);
    if( sqlite3MallocFailed() ){
      sqliteFree(zName);
      sqlite3DeleteTable(0, pTab);
      return 0;
    }

    /* Make sure the column name is unique.  If the name is not unique,
    ** append a integer to the name so that it becomes unique.
    */
    zBasename = zName;
    for(j=cnt=0; j<i; j++){
      if( sqlite3StrICmp(aCol[j].zName, zName)==0 ){
        zName = sqlite3MPrintf("%s:%d", zBasename, ++cnt);
        j = -1;
        if( zName==0 ) break;
      }
    }
    if( zBasename!=zName ){
      sqliteFree(zBasename);
    }
    pCol->zName = zName;

    /* Get the typename, type affinity, and collating sequence for the
    ** column.
    */
    memset(&sNC, 0, sizeof(sNC));
    sNC.pSrcList = pSelect->pSrc;
    zType = sqliteStrDup(columnType(&sNC, p, 0, 0, 0));
    pCol->zType = zType;
    pCol->affinity = sqlite3ExprAffinity(p);
    pColl = sqlite3ExprCollSeq(pParse, p);
    if( pColl ){
      pCol->zColl = sqliteStrDup(pColl->zName);
    }
  }
  pTab->iPKey = -1;
  return pTab;
}

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int sqlite3Select ( Parse pParse,
Select p,
int  eDest,
int  iParm,
Select pParent,
int  parentTab,
int pParentAgg,
char *  aff 
)

Definition at line 2760 of file select.c.

 {
  int i, j;              /* Loop counters */
  WhereInfo *pWInfo;     /* Return from sqlite3WhereBegin() */
  Vdbe *v;               /* The virtual machine under construction */
  int isAgg;             /* True for select lists like "count(*)" */
  ExprList *pEList;      /* List of columns to extract. */
  SrcList *pTabList;     /* List of tables to select from */
  Expr *pWhere;          /* The WHERE clause.  May be NULL */
  ExprList *pOrderBy;    /* The ORDER BY clause.  May be NULL */
  ExprList *pGroupBy;    /* The GROUP BY clause.  May be NULL */
  Expr *pHaving;         /* The HAVING clause.  May be NULL */
  int isDistinct;        /* True if the DISTINCT keyword is present */
  int distinct;          /* Table to use for the distinct set */
  int rc = 1;            /* Value to return from this function */
  int addrSortIndex;     /* Address of an OP_OpenVirtual instruction */
  AggInfo sAggInfo;      /* Information used by aggregate queries */
  int iEnd;              /* Address of the end of the query */

  if( p==0 || sqlite3MallocFailed() || pParse->nErr ){
    return 1;
  }
  if( sqlite3AuthCheck(pParse, SQLITE_SELECT, 0, 0, 0) ) return 1;
  memset(&sAggInfo, 0, sizeof(sAggInfo));

#ifndef SQLITE_OMIT_COMPOUND_SELECT
  /* If there is are a sequence of queries, do the earlier ones first.
  */
  if( p->pPrior ){
    if( p->pRightmost==0 ){
      Select *pLoop;
      for(pLoop=p; pLoop; pLoop=pLoop->pPrior){
        pLoop->pRightmost = p;
      }
    }
    return multiSelect(pParse, p, eDest, iParm, aff);
  }
#endif

  pOrderBy = p->pOrderBy;
  if( IgnorableOrderby(eDest) ){
    p->pOrderBy = 0;
  }
  if( sqlite3SelectResolve(pParse, p, 0) ){
    goto select_end;
  }
  p->pOrderBy = pOrderBy;

  /* Make local copies of the parameters for this query.
  */
  pTabList = p->pSrc;
  pWhere = p->pWhere;
  pGroupBy = p->pGroupBy;
  pHaving = p->pHaving;
  isAgg = p->isAgg;
  isDistinct = p->isDistinct;
  pEList = p->pEList;
  if( pEList==0 ) goto select_end;

  /* 
  ** Do not even attempt to generate any code if we have already seen
  ** errors before this routine starts.
  */
  if( pParse->nErr>0 ) goto select_end;

  /* If writing to memory or generating a set
  ** only a single column may be output.
  */
#ifndef SQLITE_OMIT_SUBQUERY
  if( (eDest==SRT_Mem || eDest==SRT_Set) && pEList->nExpr>1 ){
    sqlite3ErrorMsg(pParse, "only a single result allowed for "
       "a SELECT that is part of an expression");
    goto select_end;
  }
#endif

  /* ORDER BY is ignored for some destinations.
  */
  if( IgnorableOrderby(eDest) ){
    pOrderBy = 0;
  }

  /* Begin generating code.
  */
  v = sqlite3GetVdbe(pParse);
  if( v==0 ) goto select_end;

  /* Generate code for all sub-queries in the FROM clause
  */
#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
  for(i=0; i<pTabList->nSrc; i++){
    const char *zSavedAuthContext = 0;
    int needRestoreContext;
    struct SrcList_item *pItem = &pTabList->a[i];

    if( pItem->pSelect==0 || pItem->isPopulated ) continue;
    if( pItem->zName!=0 ){
      zSavedAuthContext = pParse->zAuthContext;
      pParse->zAuthContext = pItem->zName;
      needRestoreContext = 1;
    }else{
      needRestoreContext = 0;
    }
    sqlite3Select(pParse, pItem->pSelect, SRT_VirtualTab, 
                 pItem->iCursor, p, i, &isAgg, 0);
    if( needRestoreContext ){
      pParse->zAuthContext = zSavedAuthContext;
    }
    pTabList = p->pSrc;
    pWhere = p->pWhere;
    if( !IgnorableOrderby(eDest) ){
      pOrderBy = p->pOrderBy;
    }
    pGroupBy = p->pGroupBy;
    pHaving = p->pHaving;
    isDistinct = p->isDistinct;
  }
#endif

  /* Check for the special case of a min() or max() function by itself
  ** in the result set.
  */
  if( simpleMinMaxQuery(pParse, p, eDest, iParm) ){
    rc = 0;
    goto select_end;
  }

  /* Check to see if this is a subquery that can be "flattened" into its parent.
  ** If flattening is a possiblity, do so and return immediately.  
  */
#ifndef SQLITE_OMIT_VIEW
  if( pParent && pParentAgg &&
      flattenSubquery(pParent, parentTab, *pParentAgg, isAgg) ){
    if( isAgg ) *pParentAgg = 1;
    goto select_end;
  }
#endif

  /* If there is an ORDER BY clause, resolve any collation sequences
  ** names that have been explicitly specified and create a sorting index.
  **
  ** This sorting index might end up being unused if the data can be 
  ** extracted in pre-sorted order.  If that is the case, then the
  ** OP_OpenVirtual instruction will be changed to an OP_Noop once
  ** we figure out that the sorting index is not needed.  The addrSortIndex
  ** variable is used to facilitate that change.
  */
  if( pOrderBy ){
    struct ExprList_item *pTerm;
    KeyInfo *pKeyInfo;
    for(i=0, pTerm=pOrderBy->a; i<pOrderBy->nExpr; i++, pTerm++){
      if( pTerm->zName ){
        pTerm->pExpr->pColl = sqlite3LocateCollSeq(pParse, pTerm->zName, -1);
      }
    }
    if( pParse->nErr ){
      goto select_end;
    }
    pKeyInfo = keyInfoFromExprList(pParse, pOrderBy);
    pOrderBy->iECursor = pParse->nTab++;
    p->addrOpenVirt[2] = addrSortIndex =
       sqlite3VdbeOp3(v, OP_OpenVirtual, pOrderBy->iECursor, pOrderBy->nExpr+2, 
                        (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
  }else{
    addrSortIndex = -1;
  }

  /* If the output is destined for a temporary table, open that table.
  */
  if( eDest==SRT_VirtualTab ){
    sqlite3VdbeAddOp(v, OP_OpenVirtual, iParm, pEList->nExpr);
  }

  /* Set the limiter.
  */
  iEnd = sqlite3VdbeMakeLabel(v);
  computeLimitRegisters(pParse, p, iEnd);

  /* Open a virtual index to use for the distinct set.
  */
  if( isDistinct ){
    KeyInfo *pKeyInfo;
    distinct = pParse->nTab++;
    pKeyInfo = keyInfoFromExprList(pParse, p->pEList);
    sqlite3VdbeOp3(v, OP_OpenVirtual, distinct, 0, 
                        (char*)pKeyInfo, P3_KEYINFO_HANDOFF);
  }else{
    distinct = -1;
  }

  /* Aggregate and non-aggregate queries are handled differently */
  if( !isAgg && pGroupBy==0 ){
    /* This case is for non-aggregate queries
    ** Begin the database scan
    */
    pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pOrderBy);
    if( pWInfo==0 ) goto select_end;

    /* If sorting index that was created by a prior OP_OpenVirtual 
    ** instruction ended up not being needed, then change the OP_OpenVirtual
    ** into an OP_Noop.
    */
    if( addrSortIndex>=0 && pOrderBy==0 ){
      sqlite3VdbeChangeToNoop(v, addrSortIndex, 1);
      p->addrOpenVirt[2] = -1;
    }

    /* Use the standard inner loop
    */
    if( selectInnerLoop(pParse, p, pEList, 0, 0, pOrderBy, distinct, eDest,
                    iParm, pWInfo->iContinue, pWInfo->iBreak, aff) ){
       goto select_end;
    }

    /* End the database scan loop.
    */
    sqlite3WhereEnd(pWInfo);
  }else{
    /* This is the processing for aggregate queries */
    NameContext sNC;    /* Name context for processing aggregate information */
    int iAMem;          /* First Mem address for storing current GROUP BY */
    int iBMem;          /* First Mem address for previous GROUP BY */
    int iUseFlag;       /* Mem address holding flag indicating that at least
                        ** one row of the input to the aggregator has been
                        ** processed */
    int iAbortFlag;     /* Mem address which causes query abort if positive */
    int groupBySort;    /* Rows come from source in GROUP BY order */


    /* The following variables hold addresses or labels for parts of the
    ** virtual machine program we are putting together */
    int addrOutputRow;      /* Start of subroutine that outputs a result row */
    int addrSetAbort;       /* Set the abort flag and return */
    int addrInitializeLoop; /* Start of code that initializes the input loop */
    int addrTopOfLoop;      /* Top of the input loop */
    int addrGroupByChange;  /* Code that runs when any GROUP BY term changes */
    int addrProcessRow;     /* Code to process a single input row */
    int addrEnd;            /* End of all processing */
    int addrSortingIdx;     /* The OP_OpenVirtual for the sorting index */
    int addrReset;          /* Subroutine for resetting the accumulator */

    addrEnd = sqlite3VdbeMakeLabel(v);

    /* Convert TK_COLUMN nodes into TK_AGG_COLUMN and make entries in
    ** sAggInfo for all TK_AGG_FUNCTION nodes in expressions of the
    ** SELECT statement.
    */
    memset(&sNC, 0, sizeof(sNC));
    sNC.pParse = pParse;
    sNC.pSrcList = pTabList;
    sNC.pAggInfo = &sAggInfo;
    sAggInfo.nSortingColumn = pGroupBy ? pGroupBy->nExpr+1 : 0;
    sAggInfo.pGroupBy = pGroupBy;
    if( sqlite3ExprAnalyzeAggList(&sNC, pEList) ){
      goto select_end;
    }
    if( sqlite3ExprAnalyzeAggList(&sNC, pOrderBy) ){
      goto select_end;
    }
    if( pHaving && sqlite3ExprAnalyzeAggregates(&sNC, pHaving) ){
      goto select_end;
    }
    sAggInfo.nAccumulator = sAggInfo.nColumn;
    for(i=0; i<sAggInfo.nFunc; i++){
      if( sqlite3ExprAnalyzeAggList(&sNC, sAggInfo.aFunc[i].pExpr->pList) ){
        goto select_end;
      }
    }
    if( sqlite3MallocFailed() ) goto select_end;

    /* Processing for aggregates with GROUP BY is very different and
    ** much more complex tha aggregates without a GROUP BY.
    */
    if( pGroupBy ){
      KeyInfo *pKeyInfo;  /* Keying information for the group by clause */

      /* Create labels that we will be needing
      */
     
      addrInitializeLoop = sqlite3VdbeMakeLabel(v);
      addrGroupByChange = sqlite3VdbeMakeLabel(v);
      addrProcessRow = sqlite3VdbeMakeLabel(v);

      /* If there is a GROUP BY clause we might need a sorting index to
      ** implement it.  Allocate that sorting index now.  If it turns out
      ** that we do not need it after all, the OpenVirtual instruction
      ** will be converted into a Noop.  
      */
      sAggInfo.sortingIdx = pParse->nTab++;
      pKeyInfo = keyInfoFromExprList(pParse, pGroupBy);
      addrSortingIdx =
          sqlite3VdbeOp3(v, OP_OpenVirtual, sAggInfo.sortingIdx,
                         sAggInfo.nSortingColumn,
                         (char*)pKeyInfo, P3_KEYINFO_HANDOFF);

      /* Initialize memory locations used by GROUP BY aggregate processing
      */
      iUseFlag = pParse->nMem++;
      iAbortFlag = pParse->nMem++;
      iAMem = pParse->nMem;
      pParse->nMem += pGroupBy->nExpr;
      iBMem = pParse->nMem;
      pParse->nMem += pGroupBy->nExpr;
      sqlite3VdbeAddOp(v, OP_MemInt, 0, iAbortFlag);
      VdbeComment((v, "# clear abort flag"));
      sqlite3VdbeAddOp(v, OP_MemInt, 0, iUseFlag);
      VdbeComment((v, "# indicate accumulator empty"));
      sqlite3VdbeAddOp(v, OP_Goto, 0, addrInitializeLoop);

      /* Generate a subroutine that outputs a single row of the result
      ** set.  This subroutine first looks at the iUseFlag.  If iUseFlag
      ** is less than or equal to zero, the subroutine is a no-op.  If
      ** the processing calls for the query to abort, this subroutine
      ** increments the iAbortFlag memory location before returning in
      ** order to signal the caller to abort.
      */
      addrSetAbort = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_MemInt, 1, iAbortFlag);
      VdbeComment((v, "# set abort flag"));
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      addrOutputRow = sqlite3VdbeCurrentAddr(v);
      sqlite3VdbeAddOp(v, OP_IfMemPos, iUseFlag, addrOutputRow+2);
      VdbeComment((v, "# Groupby result generator entry point"));
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      finalizeAggFunctions(pParse, &sAggInfo);
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrOutputRow+1, 1);
      }
      rc = selectInnerLoop(pParse, p, p->pEList, 0, 0, pOrderBy,
                           distinct, eDest, iParm, 
                           addrOutputRow+1, addrSetAbort, aff);
      if( rc ){
        goto select_end;
      }
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);
      VdbeComment((v, "# end groupby result generator"));

      /* Generate a subroutine that will reset the group-by accumulator
      */
      addrReset = sqlite3VdbeCurrentAddr(v);
      resetAccumulator(pParse, &sAggInfo);
      sqlite3VdbeAddOp(v, OP_Return, 0, 0);

      /* Begin a loop that will extract all source rows in GROUP BY order.
      ** This might involve two separate loops with an OP_Sort in between, or
      ** it might be a single loop that uses an index to extract information
      ** in the right order to begin with.
      */
      sqlite3VdbeResolveLabel(v, addrInitializeLoop);
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, &pGroupBy);
      if( pWInfo==0 ) goto select_end;
      if( pGroupBy==0 ){
        /* The optimizer is able to deliver rows in group by order so
        ** we do not have to sort.  The OP_OpenVirtual table will be
        ** cancelled later because we still need to use the pKeyInfo
        */
        pGroupBy = p->pGroupBy;
        groupBySort = 0;
      }else{
        /* Rows are coming out in undetermined order.  We have to push
        ** each row into a sorting index, terminate the first loop,
        ** then loop over the sorting index in order to get the output
        ** in sorted order
        */
        groupBySort = 1;
        sqlite3ExprCodeExprList(pParse, pGroupBy);
        sqlite3VdbeAddOp(v, OP_Sequence, sAggInfo.sortingIdx, 0);
        j = pGroupBy->nExpr+1;
        for(i=0; i<sAggInfo.nColumn; i++){
          struct AggInfo_col *pCol = &sAggInfo.aCol[i];
          if( pCol->iSorterColumn<j ) continue;
          if( pCol->iColumn<0 ){
            sqlite3VdbeAddOp(v, OP_Rowid, pCol->iTable, 0);
          }else{
            sqlite3VdbeAddOp(v, OP_Column, pCol->iTable, pCol->iColumn);
          }
          j++;
        }
        sqlite3VdbeAddOp(v, OP_MakeRecord, j, 0);
        sqlite3VdbeAddOp(v, OP_IdxInsert, sAggInfo.sortingIdx, 0);
        sqlite3WhereEnd(pWInfo);
        sqlite3VdbeAddOp(v, OP_Sort, sAggInfo.sortingIdx, addrEnd);
        VdbeComment((v, "# GROUP BY sort"));
        sAggInfo.useSortingIdx = 1;
      }

      /* Evaluate the current GROUP BY terms and store in b0, b1, b2...
      ** (b0 is memory location iBMem+0, b1 is iBMem+1, and so forth)
      ** Then compare the current GROUP BY terms against the GROUP BY terms
      ** from the previous row currently stored in a0, a1, a2...
      */
      addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
      for(j=0; j<pGroupBy->nExpr; j++){
        if( groupBySort ){
          sqlite3VdbeAddOp(v, OP_Column, sAggInfo.sortingIdx, j);
        }else{
          sAggInfo.directMode = 1;
          sqlite3ExprCode(pParse, pGroupBy->a[j].pExpr);
        }
        sqlite3VdbeAddOp(v, OP_MemStore, iBMem+j, j<pGroupBy->nExpr-1);
      }
      for(j=pGroupBy->nExpr-1; j>=0; j--){
        if( j<pGroupBy->nExpr-1 ){
          sqlite3VdbeAddOp(v, OP_MemLoad, iBMem+j, 0);
        }
        sqlite3VdbeAddOp(v, OP_MemLoad, iAMem+j, 0);
        if( j==0 ){
          sqlite3VdbeAddOp(v, OP_Eq, 0x200, addrProcessRow);
        }else{
          sqlite3VdbeAddOp(v, OP_Ne, 0x200, addrGroupByChange);
        }
        sqlite3VdbeChangeP3(v, -1, (void*)pKeyInfo->aColl[j], P3_COLLSEQ);
      }

      /* Generate code that runs whenever the GROUP BY changes.
      ** Change in the GROUP BY are detected by the previous code
      ** block.  If there were no changes, this block is skipped.
      **
      ** This code copies current group by terms in b0,b1,b2,...
      ** over to a0,a1,a2.  It then calls the output subroutine
      ** and resets the aggregate accumulator registers in preparation
      ** for the next GROUP BY batch.
      */
      sqlite3VdbeResolveLabel(v, addrGroupByChange);
      for(j=0; j<pGroupBy->nExpr; j++){
        sqlite3VdbeAddOp(v, OP_MemMove, iAMem+j, iBMem+j);
      }
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
      VdbeComment((v, "# output one row"));
      sqlite3VdbeAddOp(v, OP_IfMemPos, iAbortFlag, addrEnd);
      VdbeComment((v, "# check abort flag"));
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrReset);
      VdbeComment((v, "# reset accumulator"));

      /* Update the aggregate accumulators based on the content of
      ** the current row
      */
      sqlite3VdbeResolveLabel(v, addrProcessRow);
      updateAccumulator(pParse, &sAggInfo);
      sqlite3VdbeAddOp(v, OP_MemInt, 1, iUseFlag);
      VdbeComment((v, "# indicate data in accumulator"));

      /* End of the loop
      */
      if( groupBySort ){
        sqlite3VdbeAddOp(v, OP_Next, sAggInfo.sortingIdx, addrTopOfLoop);
      }else{
        sqlite3WhereEnd(pWInfo);
        sqlite3VdbeChangeToNoop(v, addrSortingIdx, 1);
      }

      /* Output the final row of result
      */
      sqlite3VdbeAddOp(v, OP_Gosub, 0, addrOutputRow);
      VdbeComment((v, "# output final row"));
      
    } /* endif pGroupBy */
    else {
      /* This case runs if the aggregate has no GROUP BY clause.  The
      ** processing is much simpler since there is only a single row
      ** of output.
      */
      resetAccumulator(pParse, &sAggInfo);
      pWInfo = sqlite3WhereBegin(pParse, pTabList, pWhere, 0);
      if( pWInfo==0 ) goto select_end;
      updateAccumulator(pParse, &sAggInfo);
      sqlite3WhereEnd(pWInfo);
      finalizeAggFunctions(pParse, &sAggInfo);
      pOrderBy = 0;
      if( pHaving ){
        sqlite3ExprIfFalse(pParse, pHaving, addrEnd, 1);
      }
      selectInnerLoop(pParse, p, p->pEList, 0, 0, 0, -1, 
                      eDest, iParm, addrEnd, addrEnd, aff);
    }
    sqlite3VdbeResolveLabel(v, addrEnd);
    
  } /* endif aggregate query */

  /* If there is an ORDER BY clause, then we need to sort the results
  ** and send them to the callback one by one.
  */
  if( pOrderBy ){
    generateSortTail(pParse, p, v, pEList->nExpr, eDest, iParm);
  }

#ifndef SQLITE_OMIT_SUBQUERY
  /* If this was a subquery, we have now converted the subquery into a
  ** temporary table.  So set the SrcList_item.isPopulated flag to prevent
  ** this subquery from being evaluated again and to force the use of
  ** the temporary table.
  */
  if( pParent ){
    assert( pParent->pSrc->nSrc>parentTab );
    assert( pParent->pSrc->a[parentTab].pSelect==p );
    pParent->pSrc->a[parentTab].isPopulated = 1;
  }
#endif

  /* Jump here to skip this query
  */
  sqlite3VdbeResolveLabel(v, iEnd);

  /* The SELECT was successfully coded.   Set the return code to 0
  ** to indicate no errors.
  */
  rc = 0;

  /* Control jumps to here if an error is encountered above, or upon
  ** successful coding of the SELECT.
  */
select_end:

  /* Identify column names if we will be using them in a callback.  This
  ** step is skipped if the output is going to some other destination.
  */
  if( rc==SQLITE_OK && eDest==SRT_Callback ){
    generateColumnNames(pParse, pTabList, pEList);
  }

  sqliteFree(sAggInfo.aCol);
  sqliteFree(sAggInfo.aFunc);
  return rc;
}

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Definition at line 88 of file select.c.

                                   {
  if( p ){
    clearSelect(p);
    sqliteFree(p);
  }
}

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Select* sqlite3SelectNew ( ExprList pEList,
SrcList pSrc,
Expr pWhere,
ExprList pGroupBy,
Expr pHaving,
ExprList pOrderBy,
int  isDistinct,
Expr pLimit,
Expr pOffset 
)

Definition at line 41 of file select.c.

 {
  Select *pNew;
  Select standin;
  pNew = sqliteMalloc( sizeof(*pNew) );
  assert( !pOffset || pLimit );   /* Can't have OFFSET without LIMIT. */
  if( pNew==0 ){
    pNew = &standin;
    memset(pNew, 0, sizeof(*pNew));
  }
  if( pEList==0 ){
    pEList = sqlite3ExprListAppend(0, sqlite3Expr(TK_ALL,0,0,0), 0);
  }
  pNew->pEList = pEList;
  pNew->pSrc = pSrc;
  pNew->pWhere = pWhere;
  pNew->pGroupBy = pGroupBy;
  pNew->pHaving = pHaving;
  pNew->pOrderBy = pOrderBy;
  pNew->isDistinct = isDistinct;
  pNew->op = TK_SELECT;
  pNew->pLimit = pLimit;
  pNew->pOffset = pOffset;
  pNew->iLimit = -1;
  pNew->iOffset = -1;
  pNew->addrOpenVirt[0] = -1;
  pNew->addrOpenVirt[1] = -1;
  pNew->addrOpenVirt[2] = -1;
  if( pNew==&standin) {
    clearSelect(pNew);
    pNew = 0;
  }
  return pNew;
}

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int sqlite3SelectResolve ( Parse pParse,
Select p,
NameContext pOuterNC 
)

Definition at line 2499 of file select.c.

 {
  ExprList *pEList;          /* Result set. */
  int i;                     /* For-loop variable used in multiple places */
  NameContext sNC;           /* Local name-context */
  ExprList *pGroupBy;        /* The group by clause */

  /* If this routine has run before, return immediately. */
  if( p->isResolved ){
    assert( !pOuterNC );
    return SQLITE_OK;
  }
  p->isResolved = 1;

  /* If there have already been errors, do nothing. */
  if( pParse->nErr>0 ){
    return SQLITE_ERROR;
  }

  /* Prepare the select statement. This call will allocate all cursors
  ** required to handle the tables and subqueries in the FROM clause.
  */
  if( prepSelectStmt(pParse, p) ){
    return SQLITE_ERROR;
  }

  /* Resolve the expressions in the LIMIT and OFFSET clauses. These
  ** are not allowed to refer to any names, so pass an empty NameContext.
  */
  memset(&sNC, 0, sizeof(sNC));
  sNC.pParse = pParse;
  if( sqlite3ExprResolveNames(&sNC, p->pLimit) ||
      sqlite3ExprResolveNames(&sNC, p->pOffset) ){
    return SQLITE_ERROR;
  }

  /* Set up the local name-context to pass to ExprResolveNames() to
  ** resolve the expression-list.
  */
  sNC.allowAgg = 1;
  sNC.pSrcList = p->pSrc;
  sNC.pNext = pOuterNC;

  /* Resolve names in the result set. */
  pEList = p->pEList;
  if( !pEList ) return SQLITE_ERROR;
  for(i=0; i<pEList->nExpr; i++){
    Expr *pX = pEList->a[i].pExpr;
    if( sqlite3ExprResolveNames(&sNC, pX) ){
      return SQLITE_ERROR;
    }
  }

  /* If there are no aggregate functions in the result-set, and no GROUP BY 
  ** expression, do not allow aggregates in any of the other expressions.
  */
  assert( !p->isAgg );
  pGroupBy = p->pGroupBy;
  if( pGroupBy || sNC.hasAgg ){
    p->isAgg = 1;
  }else{
    sNC.allowAgg = 0;
  }

  /* If a HAVING clause is present, then there must be a GROUP BY clause.
  */
  if( p->pHaving && !pGroupBy ){
    sqlite3ErrorMsg(pParse, "a GROUP BY clause is required before HAVING");
    return SQLITE_ERROR;
  }

  /* Add the expression list to the name-context before parsing the
  ** other expressions in the SELECT statement. This is so that
  ** expressions in the WHERE clause (etc.) can refer to expressions by
  ** aliases in the result set.
  **
  ** Minor point: If this is the case, then the expression will be
  ** re-evaluated for each reference to it.
  */
  sNC.pEList = p->pEList;
  if( sqlite3ExprResolveNames(&sNC, p->pWhere) ||
      sqlite3ExprResolveNames(&sNC, p->pHaving) ||
      processOrderGroupBy(&sNC, p->pOrderBy, "ORDER") ||
      processOrderGroupBy(&sNC, pGroupBy, "GROUP")
  ){
    return SQLITE_ERROR;
  }

  /* Make sure the GROUP BY clause does not contain aggregate functions.
  */
  if( pGroupBy ){
    struct ExprList_item *pItem;
  
    for(i=0, pItem=pGroupBy->a; i<pGroupBy->nExpr; i++, pItem++){
      if( ExprHasProperty(pItem->pExpr, EP_Agg) ){
        sqlite3ErrorMsg(pParse, "aggregate functions are not allowed in "
            "the GROUP BY clause");
        return SQLITE_ERROR;
      }
    }
  }

  return SQLITE_OK;
}

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static int sqliteProcessJoin ( Parse pParse,
Select p 
) [static]

Definition at line 281 of file select.c.

                                                      {
  SrcList *pSrc;                  /* All tables in the FROM clause */
  int i, j;                       /* Loop counters */
  struct SrcList_item *pLeft;     /* Left table being joined */
  struct SrcList_item *pRight;    /* Right table being joined */

  pSrc = p->pSrc;
  pLeft = &pSrc->a[0];
  pRight = &pLeft[1];
  for(i=0; i<pSrc->nSrc-1; i++, pRight++, pLeft++){
    Table *pLeftTab = pLeft->pTab;
    Table *pRightTab = pRight->pTab;

    if( pLeftTab==0 || pRightTab==0 ) continue;

    /* When the NATURAL keyword is present, add WHERE clause terms for
    ** every column that the two tables have in common.
    */
    if( pLeft->jointype & JT_NATURAL ){
      if( pLeft->pOn || pLeft->pUsing ){
        sqlite3ErrorMsg(pParse, "a NATURAL join may not have "
           "an ON or USING clause", 0);
        return 1;
      }
      for(j=0; j<pLeftTab->nCol; j++){
        char *zName = pLeftTab->aCol[j].zName;
        if( columnIndex(pRightTab, zName)>=0 ){
          addWhereTerm(zName, pLeftTab, pLeft->zAlias, 
                              pRightTab, pRight->zAlias,
                              pRight->iCursor, &p->pWhere);
          
        }
      }
    }

    /* Disallow both ON and USING clauses in the same join
    */
    if( pLeft->pOn && pLeft->pUsing ){
      sqlite3ErrorMsg(pParse, "cannot have both ON and USING "
        "clauses in the same join");
      return 1;
    }

    /* Add the ON clause to the end of the WHERE clause, connected by
    ** an AND operator.
    */
    if( pLeft->pOn ){
      setJoinExpr(pLeft->pOn, pRight->iCursor);
      p->pWhere = sqlite3ExprAnd(p->pWhere, pLeft->pOn);
      pLeft->pOn = 0;
    }

    /* Create extra terms on the WHERE clause for each column named
    ** in the USING clause.  Example: If the two tables to be joined are 
    ** A and B and the USING clause names X, Y, and Z, then add this
    ** to the WHERE clause:    A.X=B.X AND A.Y=B.Y AND A.Z=B.Z
    ** Report an error if any column mentioned in the USING clause is
    ** not contained in both tables to be joined.
    */
    if( pLeft->pUsing ){
      IdList *pList = pLeft->pUsing;
      for(j=0; j<pList->nId; j++){
        char *zName = pList->a[j].zName;
        if( columnIndex(pLeftTab, zName)<0 || columnIndex(pRightTab, zName)<0 ){
          sqlite3ErrorMsg(pParse, "cannot join using column %s - column "
            "not present in both tables", zName);
          return 1;
        }
        addWhereTerm(zName, pLeftTab, pLeft->zAlias, 
                            pRightTab, pRight->zAlias,
                            pRight->iCursor, &p->pWhere);
      }
    }
  }
  return 0;
}

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static void substExpr ( Expr pExpr,
int  iTable,
ExprList pEList 
) [static]

Definition at line 1995 of file select.c.

                                                                {
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
    if( pExpr->iColumn<0 ){
      pExpr->op = TK_NULL;
    }else{
      Expr *pNew;
      assert( pEList!=0 && pExpr->iColumn<pEList->nExpr );
      assert( pExpr->pLeft==0 && pExpr->pRight==0 && pExpr->pList==0 );
      pNew = pEList->a[pExpr->iColumn].pExpr;
      assert( pNew!=0 );
      pExpr->op = pNew->op;
      assert( pExpr->pLeft==0 );
      pExpr->pLeft = sqlite3ExprDup(pNew->pLeft);
      assert( pExpr->pRight==0 );
      pExpr->pRight = sqlite3ExprDup(pNew->pRight);
      assert( pExpr->pList==0 );
      pExpr->pList = sqlite3ExprListDup(pNew->pList);
      pExpr->iTable = pNew->iTable;
      pExpr->iColumn = pNew->iColumn;
      pExpr->iAgg = pNew->iAgg;
      sqlite3TokenCopy(&pExpr->token, &pNew->token);
      sqlite3TokenCopy(&pExpr->span, &pNew->span);
      pExpr->pSelect = sqlite3SelectDup(pNew->pSelect);
      pExpr->flags = pNew->flags;
    }
  }else{
    substExpr(pExpr->pLeft, iTable, pEList);
    substExpr(pExpr->pRight, iTable, pEList);
    substSelect(pExpr->pSelect, iTable, pEList);
    substExprList(pExpr->pList, iTable, pEList);
  }
}

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static void substExprList ( ExprList pList,
int  iTable,
ExprList pEList 
) [static]

Definition at line 2028 of file select.c.

                                                                        {
  int i;
  if( pList==0 ) return;
  for(i=0; i<pList->nExpr; i++){
    substExpr(pList->a[i].pExpr, iTable, pEList);
  }
}

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static void substSelect ( Select p,
int  iTable,
ExprList pEList 
) [static]

Definition at line 2035 of file select.c.

                                                                {
  if( !p ) return;
  substExprList(p->pEList, iTable, pEList);
  substExprList(p->pGroupBy, iTable, pEList);
  substExprList(p->pOrderBy, iTable, pEList);
  substExpr(p->pHaving, iTable, pEList);
  substExpr(p->pWhere, iTable, pEList);
}

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static void updateAccumulator ( Parse pParse,
AggInfo pAggInfo 
) [static]

Definition at line 2660 of file select.c.

                                                               {
  Vdbe *v = pParse->pVdbe;
  int i;
  struct AggInfo_func *pF;
  struct AggInfo_col *pC;

  pAggInfo->directMode = 1;
  for(i=0, pF=pAggInfo->aFunc; i<pAggInfo->nFunc; i++, pF++){
    int nArg;
    int addrNext = 0;
    ExprList *pList = pF->pExpr->pList;
    if( pList ){
      nArg = pList->nExpr;
      sqlite3ExprCodeExprList(pParse, pList);
    }else{
      nArg = 0;
    }
    if( pF->iDistinct>=0 ){
      addrNext = sqlite3VdbeMakeLabel(v);
      assert( nArg==1 );
      codeDistinct(v, pF->iDistinct, addrNext, 1);
    }
    if( pF->pFunc->needCollSeq ){
      CollSeq *pColl = 0;
      struct ExprList_item *pItem;
      int j;
      assert( pList!=0 );  /* pList!=0 if pF->pFunc->needCollSeq is true */
      for(j=0, pItem=pList->a; !pColl && j<nArg; j++, pItem++){
        pColl = sqlite3ExprCollSeq(pParse, pItem->pExpr);
      }
      if( !pColl ){
        pColl = pParse->db->pDfltColl;
      }
      sqlite3VdbeOp3(v, OP_CollSeq, 0, 0, (char *)pColl, P3_COLLSEQ);
    }
    sqlite3VdbeOp3(v, OP_AggStep, pF->iMem, nArg, (void*)pF->pFunc, P3_FUNCDEF);
    if( addrNext ){
      sqlite3VdbeResolveLabel(v, addrNext);
    }
  }
  for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
    sqlite3ExprCode(pParse, pC->pExpr);
    sqlite3VdbeAddOp(v, OP_MemStore, pC->iMem, 1);
  }
  pAggInfo->directMode = 0;
}

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