SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains C code routines that are called by the parser
** to handle SELECT statements in SQLite.
**
** $Id: select.c,v 1.420 2008/03/26 12:46:24 drh Exp $
*/
#include "sqliteInt.h"


/*
** Delete all the content of a Select structure but do not deallocate
** the select structure itself.

** Initialize a SelectDest structure.
*/
void sqlite3SelectDestInit(SelectDest *pDest, int eDest, int iParm){
  pDest->eDest = eDest;
  pDest->iParm = iParm;
  pDest->affinity = 0;
  pDest->iMem = 0;
  pDest->nMem = 0;
}


/*
** Allocate a new Select structure and return a pointer to that
** structure.
*/

  Parse *pParse,           /* Parsing context */
  const char *zCol,        /* Name of the column */
  const Table *pTab1,      /* First table */
  const char *zAlias1,     /* Alias for first table.  May be NULL */
  const Table *pTab2,      /* Second table */
  const char *zAlias2,     /* Alias for second table.  May be NULL */
  int iRightJoinTable,     /* VDBE cursor for the right table */
  Expr **ppExpr,           /* Add the equality term to this expression */
  int isOuterJoin          /* True if dealing with an OUTER join */
){
  Expr *pE1a, *pE1b, *pE1c;
  Expr *pE2a, *pE2b, *pE2c;
  Expr *pE;

  pE1a = sqlite3CreateIdExpr(pParse, zCol);
  pE2a = sqlite3CreateIdExpr(pParse, zCol);
  if( zAlias1==0 ){
    zAlias1 = pTab1->zName;
  }
  pE1b = sqlite3CreateIdExpr(pParse, zAlias1);
  if( zAlias2==0 ){
    zAlias2 = pTab2->zName;
  }
  pE2b = sqlite3CreateIdExpr(pParse, zAlias2);
  pE1c = sqlite3PExpr(pParse, TK_DOT, pE1b, pE1a, 0);
  pE2c = sqlite3PExpr(pParse, TK_DOT, pE2b, pE2a, 0);
  pE = sqlite3PExpr(pParse, TK_EQ, pE1c, pE2c, 0);
  if( pE && isOuterJoin ){
    ExprSetProperty(pE, EP_FromJoin);
    pE->iRightJoinTable = iRightJoinTable;
  }
  *ppExpr = sqlite3ExprAnd(pParse->db,*ppExpr, pE);
}

/*

  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;
    int isOuter;

    if( pLeftTab==0 || pRightTab==0 ) continue;
    isOuter = (pRight->jointype & JT_OUTER)!=0;

    /* When the NATURAL keyword is present, add WHERE clause terms for
    ** every column that the two tables have in common.
    */
    if( pRight->jointype & JT_NATURAL ){
      if( pRight->pOn || pRight->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(pParse, zName, pLeftTab, pLeft->zAlias, 
                              pRightTab, pRight->zAlias,
                              pRight->iCursor, &p->pWhere, isOuter);
          
        }
      }
    }

    /* Disallow both ON and USING clauses in the same join
    */
    if( pRight->pOn && pRight->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( pRight->pOn ){
      if( isOuter ) setJoinExpr(pRight->pOn, pRight->iCursor);
      p->pWhere = sqlite3ExprAnd(pParse->db, p->pWhere, pRight->pOn);
      pRight->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

        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(pParse, zName, pLeftTab, pLeft->zAlias, 
                            pRightTab, pRight->zAlias,
                            pRight->iCursor, &p->pWhere, isOuter);
      }
    }
  }
  return 0;
}

/*

  if( nColumn>0 ){
    nResultCol = nColumn;
  }else{
    nResultCol = pEList->nExpr;
  }
  if( pDest->iMem==0 ){
    pDest->iMem = sqlite3GetTempRange(pParse, nResultCol);
    pDest->nMem = nResultCol;
  }else if( pDest->nMem!=nResultCol ){
    return;
  }
  regResult = pDest->iMem;
  if( nColumn>0 ){
    for(i=0; i<nColumn; i++){
      sqlite3VdbeAddOp3(v, OP_Column, srcTab, i, regResult+i);
    }
  }else if( eDest!=SRT_Exists ){

    }

    sqlite3_free(pKeyInfo);
  }

multi_select_end:
  pDest->iMem = dest.iMem;
  pDest->nMem = dest.nMem;
  return rc;
}
#endif /* SQLITE_OMIT_COMPOUND_SELECT */

#ifndef SQLITE_OMIT_VIEW
/* Forward Declarations */
static void substExprList(sqlite3*, ExprList*, int, ExprList*);

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.681 2008/03/26 12:46:24 drh Exp $
*/
#ifndef _SQLITEINT_H_
#define _SQLITEINT_H_

/*
** Include the configuration header output by 'configure' if it was run
** (otherwise we get an empty default).

*/
typedef struct SelectDest SelectDest;
struct SelectDest {
  u8 eDest;         /* How to dispose of the results */
  u8 affinity;      /* Affinity used when eDest==SRT_Set */
  int iParm;        /* A parameter used by the eDest disposal method */
  int iMem;         /* Base register where results are written */
  int nMem;         /* Number of registers allocated */
};

/*
** An SQL parser context.  A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing UNION, INTERSECT and EXCEPT operators
# in SELECT statements.
#
# $Id: select4.test,v 1.27 2008/03/26 12:46:25 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl

# Most tests in this file depend on compound-select. But there are a couple
# right at the end that test DISTINCT, so we cannot omit the entire file.
#

} {}
do_test select4-10.8 {
  execsql {
    SELECT DISTINCT log FROM t1 ORDER BY log LIMIT 0 OFFSET 3
  }
} {}
do_test select4-10.9 {

  execsql {
    SELECT DISTINCT max(n), log FROM t1 ORDER BY +log; -- LIMIT 2 OFFSET 1
  }
} {31 5}

# Make sure compound SELECTs with wildly different numbers of columns
# do not cause assertion faults due to register allocation issues.
#
do_test select4-11.1 {
  catchsql {
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    UNION
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of UNION do not have the same number of result columns}}
do_test select4-11.2 {
  catchsql {
    SELECT x FROM t2
    UNION
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
  }
} {1 {SELECTs to the left and right of UNION do not have the same number of result columns}}
do_test select4-11.3 {
  catchsql {
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    UNION ALL
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of UNION ALL do not have the same number of result columns}}
do_test select4-11.4 {
  catchsql {
    SELECT x FROM t2
    UNION ALL
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
  }
} {1 {SELECTs to the left and right of UNION ALL do not have the same number of result columns}}
do_test select4-11.5 {
  catchsql {
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    EXCEPT
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of EXCEPT do not have the same number of result columns}}
do_test select4-11.6 {
  catchsql {
    SELECT x FROM t2
    EXCEPT
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
  }
} {1 {SELECTs to the left and right of EXCEPT do not have the same number of result columns}}
do_test select4-11.7 {
  catchsql {
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    INTERSECT
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of INTERSECT do not have the same number of result columns}}
do_test select4-11.8 {
  catchsql {
    SELECT x FROM t2
    INTERSECT
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
  }
} {1 {SELECTs to the left and right of INTERSECT do not have the same number of result columns}}

do_test select4-11.11 {
  catchsql {
    SELECT x FROM t2
    UNION
    SELECT x FROM t2
    UNION ALL
    SELECT x FROM t2
    EXCEPT
    SELECT x FROM t2
    INTERSECT
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
  }
} {1 {SELECTs to the left and right of INTERSECT do not have the same number of result columns}}
do_test select4-11.12 {
  catchsql {
    SELECT x FROM t2
    UNION
    SELECT x FROM t2
    UNION ALL
    SELECT x FROM t2
    EXCEPT
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    EXCEPT
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of EXCEPT do not have the same number of result columns}}
do_test select4-11.13 {
  catchsql {
    SELECT x FROM t2
    UNION
    SELECT x FROM t2
    UNION ALL
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    UNION ALL
    SELECT x FROM t2
    EXCEPT
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of UNION ALL do not have the same number of result columns}}
do_test select4-11.14 {
  catchsql {
    SELECT x FROM t2
    UNION
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    UNION
    SELECT x FROM t2
    UNION ALL
    SELECT x FROM t2
    EXCEPT
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of UNION do not have the same number of result columns}}
do_test select4-11.15 {
  catchsql {
    SELECT x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x,x FROM t2
    UNION
    SELECT x FROM t2
    INTERSECT
    SELECT x FROM t2
    UNION ALL
    SELECT x FROM t2
    EXCEPT
    SELECT x FROM t2
  }
} {1 {SELECTs to the left and right of UNION do not have the same number of result columns}}

finish_test