SQLite

**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains routines used for analyzing expressions and
** for generating VDBE code that evaluates expressions in SQLite.
**
** $Id: expr.c,v 1.221 2005/08/25 12:45:04 drh Exp $
*/
#include "sqliteInt.h"
#include <ctype.h>

/*
** Return the 'affinity' of the expression pExpr if any.
**

** The return value from xFunc determines whether the tree walk continues.
** 0 means continue walking the tree.  1 means do not walk children
** of the current node but continue with siblings.  2 means abandon
** the tree walk completely.
**
** The return value from this routine is 1 to abandon the tree walk
** and 0 to continue.
**
** NOTICE:  This routine does *not* descend into subqueries.
*/
static int walkExprList(ExprList *, int (*)(void *, Expr*), void *);
static int walkExprTree(Expr *pExpr, int (*xFunc)(void*,Expr*), void *pArg){
  int rc;
  if( pExpr==0 ) return 0;
  rc = (*xFunc)(pArg, pExpr);
  if( rc==0 ){

    case TK_AGG_FUNCTION:
#ifndef SQLITE_OMIT_SUBQUERY
    case TK_SELECT:
    case TK_EXISTS:
#endif
      *((int*)pArg) = 0;
      return 2;
    case TK_IN:
      if( pExpr->pSelect ){
        *((int*)pArg) = 0;
        return 2;
      }
    default:
      return 0;
  }
}

/*
** Walk an expression tree.  Return 1 if the expression is constant

# 2005 January 19
#
# 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.
#
#*************************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing correlated subqueries
#
# $Id: subquery.test,v 1.12 2005/08/25 12:45:04 drh Exp $
#

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

ifcapable !subquery {
  finish_test

do_test subquery-5.2 {
  # This is the key test.  The subquery should have only run once.  If
  # The double-quoted identifier "two" were causing the subquery to be
  # processed as a correlated subquery, then it would have run 4 times.
  set callcnt
} {1}


# Ticket #1380.  Make sure correlated subqueries on an IN clause work
# correctly when the left-hand side of the IN operator is constant.
#
do_test subquery-6.1 {
  set callcnt 0
  execsql {
    SELECT x FROM t4 WHERE 1 IN (SELECT callcnt(count(*)) FROM t5 WHERE a=y)
  }
} {one two three four}
do_test subquery-6.2 {
  set callcnt
} {4}
do_test subquery-6.3 {
  set callcnt 0
  execsql {
    SELECT x FROM t4 WHERE 1 IN (SELECT callcnt(count(*)) FROM t5 WHERE a=1)
  }
} {one two three four}
do_test subquery-6.4 {
  set callcnt
} {1}





finish_test