SQLite

** This module contains C code that generates VDBE code used to process
** the WHERE clause of SQL statements.  This module is reponsible for
** generating the code that loops through a table looking for applicable
** rows.  Indices are selected and used to speed the search when doing
** so is applicable.  Because this module is responsible for selecting
** indices, you might also think of this module as the "query optimizer".
**
** $Id: where.c,v 1.134 2005/02/02 01:10:45 danielk1977 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.

        k = iDirectGt[i];
        assert( k<nExpr );
        pTerm = &aExpr[k];
        pX = pTerm->p;
        assert( pX!=0 );
        assert( pTerm->idxLeft==iCur );
        sqlite3ExprCode(pParse, pX->pRight);
        sqlite3VdbeAddOp(v, OP_ForceInt, pX->op==TK_LE || pX->op==TK_GT, brk);
        sqlite3VdbeAddOp(v, bRev ? OP_MoveLt : OP_MoveGe, iCur, brk);
        VdbeComment((v, "pk"));
        disableTerm(pLevel, &pTerm->p);
      }else{
        sqlite3VdbeAddOp(v, bRev ? OP_Last : OP_Rewind, iCur, brk);
      }
      if( iDirectLt[i]>=0 ){

# 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 CREATE TABLE statement.
#
# $Id: sort.test,v 1.19 2005/02/02 01:10:45 danielk1977 Exp $

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

# Create a bunch of data to sort against
#
do_test sort-1.0 {

} {2 3}
do_test sort-9.7 {
  execsql {
    SELECT x FROM t6 WHERE y>'1'
  }
} {3}
} ;# endif bloblit

# Ticket #1092 - ORDER BY on rowid fields.
do_test sort-10.1 {
  execsql {
    CREATE TABLE t7(c INTEGER PRIMARY KEY);
    INSERT INTO t7 VALUES(1);
    INSERT INTO t7 VALUES(2);
    INSERT INTO t7 VALUES(3);
    INSERT INTO t7 VALUES(4);
  }
} {}
do_test sort-10.2 {
  execsql {
    SELECT c FROM t7 WHERE c<=3 ORDER BY c DESC;
  }
} {3 2 1}
do_test sort-10.3 {
  execsql {
    SELECT c FROM t7 WHERE c<3 ORDER BY c DESC;
  }
} {2 1}

finish_test