SQLite

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  Also found here are subroutines
** to generate VDBE code to evaluate expressions.
**
** $Id: where.c,v 1.39 2002/04/02 01:58:58 drh Exp $
*/
#include "sqliteInt.h"

/*
** The query generator uses an array of instances of this structure to
** help it analyze the subexpressions of the WHERE clause.  Each WHERE
** clause subexpression is separated from the others by an AND operator.

    return 1<< (p->iTable - base);
  }
  if( p->pRight ){
    mask = exprTableUsage(base, p->pRight);
  }
  if( p->pLeft ){
    mask |= exprTableUsage(base, p->pLeft);
  }
  if( p->pList ){
    int i;
    for(i=0; i<p->pList->nExpr; i++){
      mask |= exprTableUsage(base, p->pList->a[i].pExpr);
    }
  }
  return mask;
}

/*
** Return TRUE if the given operator is one of the operators that is
** allowed for an indexable WHERE clause.  The allowed operators are

# 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.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this file is testing the SELECT statement.
#
# $Id: select2.test,v 1.17 2002/04/02 01:58:58 drh Exp $

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

# Create a table with some data
#
execsql {CREATE TABLE tbl1(f1 int, f2 int)}

#
do_test select2-3.3 {
  execsql {DROP INDEX idx1}
  set sqlite_search_count 0
  execsql {SELECT f1 FROM tbl2 WHERE f2==2000}
  set sqlite_search_count
} {29999}

# Make sure we can optimize functions in the WHERE clause that
# use fields from two or more different table.  (Bug #6)
#
do_test select2-4.1 {
  execsql {
    CREATE TABLE aa(a);
    CREATE TABLE bb(b);
    INSERT INTO aa VALUES(1);
    INSERT INTO aa VALUES(3);
    INSERT INTO bb VALUES(2);
    INSERT INTO bb VALUES(4);
    SELECT * FROM aa, bb WHERE max(a,b)>2;
  }
} {1 4 3 2 3 4}

finish_test

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

chng {2002 Apr 01 (2.4.5)} {
<li>Bug fix: Correctly handle functions that appear in the WHERE clause
    of a SELECT.</li>
<li>When the PRAGMA vdbe_trace=ON is set, correctly print the P3 operand
    value when it is a pointer to a structure rather than a pointer to
    a string.</li>
<li>When inserting an explicit NULL into an INTEGER PRIMARY KEY, convert
    the NULL value into a unique key automatically.</li>
}

chng {2002 Mar 24 (2.4.4)} {
<li>Allow "VIEW" to be a column name</li>
<li>Added support for CASE expressions (patch from Dan Kennedy)</li>