**    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 1.75 2002/03/07 02:02:51 drh Exp $
*/
#include "sqliteInt.h"

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

/*
** Scan through the expression pExpr.  Replace every reference to
** a column in table number iTable with a copy of the corresponding
** entry in pEList.  When make a copy of pEList, change references

** to columns in table iSub into references to table iTable.
**
** This routine is part of the flattening procedure.  A subquery
** whose result set is defined by pEList appears as entry in the
** FROM clause of a SELECT such that the VDBE cursor assigned to that
** FORM clause entry is iTable.  This routine make the necessary 
** changes to pExpr so that it refers directly to the source table
** of the subquery rather the result set of the subquery.
*/
static void substExpr(Expr *pExpr, int iTable, ExprList *pEList, int iSub){
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable ){
    Expr *pNew;
    assert( pEList!=0 && pExpr->iColumn>=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;
    pExpr->pLeft = sqliteExprDup(pNew->pLeft);
    pExpr->pRight = sqliteExprDup(pNew->pRight);
    pExpr->pList = sqliteExprListDup(pNew->pList);

**    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 1.76 2002/03/14 14:33:31 drh Exp $
*/
#include "sqliteInt.h"

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

/*
** Scan through the expression pExpr.  Replace every reference to
** a column in table number iTable with a copy of the corresponding
** entry in pEList.  (But leave references to the ROWID column 
** unchanged.)  When making a copy of an expression in pEList, change
** references to columns in table iSub into references to table iTable.
**
** This routine is part of the flattening procedure.  A subquery
** whose result set is defined by pEList appears as entry in the
** FROM clause of a SELECT such that the VDBE cursor assigned to that
** FORM clause entry is iTable.  This routine make the necessary 
** changes to pExpr so that it refers directly to the source table
** of the subquery rather the result set of the subquery.
*/
static void substExpr(Expr *pExpr, int iTable, ExprList *pEList, int iSub){
  if( pExpr==0 ) return;
  if( pExpr->op==TK_COLUMN && pExpr->iTable==iTable && pExpr->iColumn>=0 ){
    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;
    pExpr->pLeft = sqliteExprDup(pNew->pLeft);
    pExpr->pRight = sqliteExprDup(pNew->pRight);
    pExpr->pList = sqliteExprListDup(pNew->pList);

proc chng {date desc} {
  puts "<DT><B>$date</B></DT>"
  puts "<DD><P><UL>$desc</UL></P></DD>"
}

chng {2002 Mar 13 (2.4.1)} {
<li>Using an unnamed subquery in a FROM clause would cause a segfault.</p>
<li>The parser insist on seeing a semicolon or the end of input before
    executing a statement.  This avoids an accidental disaster if the
    WHERE keyword is misspelled in an UPDATE or DELETE statement.</li>
}


chng {2002 Mar 10 (2.4.0)} {
<li>Change the name of the sanity_check PRAGMA to <b>integrity_check</b>

proc chng {date desc} {
  puts "<DT><B>$date</B></DT>"
  puts "<DD><P><UL>$desc</UL></P></DD>"
}

chng {2002 Mar 13 (2.4.1)} {
<li>Using an unnamed subquery in a FROM clause would cause a segfault.</li>
<li>The parser now insists on seeing a semicolon or the end of input before
    executing a statement.  This avoids an accidental disaster if the
    WHERE keyword is misspelled in an UPDATE or DELETE statement.</li>
}


chng {2002 Mar 10 (2.4.0)} {
<li>Change the name of the sanity_check PRAGMA to <b>integrity_check</b>