SQLite

  
/* Opcode: String P1 P2 P3 P4 P5
** Synopsis: r[P2]='P4' (len=P1)
**
** The string value P4 of length P1 (bytes) is stored in register P2.
**
** If P5!=0 and the content of register P3 is greater than zero, then
** the datatype of the register P2 is converted to BLOB.  The content is
** the same sequence of bytes, it is merely interpreted as a BLOB instead
** of a string, as if it had been CAST.
*/
case OP_String: {          /* out2-prerelease */
  assert( pOp->p4.z!=0 );
  pOut->flags = MEM_Str|MEM_Static|MEM_Term;
  pOut->z = pOp->p4.z;
  pOut->n = pOp->p1;
  pOut->enc = encoding;

  WhereMaskSet *pMaskSet;          /* Set of table index masks */
  Expr *pExpr;                     /* The expression to be analyzed */
  Bitmask prereqLeft;              /* Prerequesites of the pExpr->pLeft */
  Bitmask prereqAll;               /* Prerequesites of pExpr */
  Bitmask extraRight = 0;          /* Extra dependencies on LEFT JOIN */
  Expr *pStr1 = 0;                 /* RHS of LIKE/GLOB operator */
  int isComplete = 0;              /* RHS of LIKE/GLOB ends with wildcard */
  int noCase = 0;                  /* uppercase equivalent to lowercase */
  int op;                          /* Top-level operator.  pExpr->op */
  Parse *pParse = pWInfo->pParse;  /* Parsing context */
  sqlite3 *db = pParse->db;        /* Database connection */

  if( db->mallocFailed ){
    return;
  }

  }
#endif /* SQLITE_OMIT_OR_OPTIMIZATION */

#ifndef SQLITE_OMIT_LIKE_OPTIMIZATION
  /* Add constraints to reduce the search space on a LIKE or GLOB
  ** operator.
  **
  ** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints
  **
  **          x>='ABC' AND x<'abd' AND x LIKE 'aBc%'
  **
  ** The last character of the prefix "abc" is incremented to form the
  ** termination condition "abd".  If case is not significant (the default
  ** for LIKE) then the lower-bound is made all uppercase and the upper-
  ** bound is made all lowercase so that the bounds also work when comparing
  ** BLOBs.
  */
  if( pWC->op==TK_AND 
   && isLikeOrGlob(pParse, pExpr, &pStr1, &isComplete, &noCase)
  ){
    Expr *pLeft;       /* LHS of LIKE/GLOB operator */
    Expr *pStr2;       /* Copy of pStr1 - RHS of LIKE/GLOB operator */
    Expr *pNewExpr1;
    Expr *pNewExpr2;
    int idxNew1;
    int idxNew2;
    Token sCollSeqName;  /* Name of collating sequence */
    const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC;


    pLeft = pExpr->x.pList->a[1].pExpr;
    pStr2 = sqlite3ExprDup(db, pStr1, 0);

    /* Convert the lower bound to upper-case and the upper bound to
    ** lower-case (upper-case is less than lower-case in ASCII) so that
    ** the range constraints also work for BLOBs
    */
    if( noCase && !pParse->db->mallocFailed ){
      int i;
      char c;
      pTerm->wtFlags |= TERM_LIKE;
      for(i=0; (c = pStr1->u.zToken[i])!=0; i++){
        pStr1->u.zToken[i] = sqlite3Toupper(c);
        pStr2->u.zToken[i] = sqlite3Tolower(c);
      }
    }

    if( !db->mallocFailed ){

**      \___________/     \______/     \_____/
**         parent          child1       child2
**
** Only the parent term was in the original WHERE clause.  The child1
** and child2 terms were added by the LIKE optimization.  If both of
** the virtual child terms are valid, then testing of the parent can be 
** skipped.
**
** Usually the parent term is marked as TERM_CODED.  But if the parent
** term was originally TERM_LIKE, then the parent gets TERM_LIKECOND instead.
** The TERM_LIKECOND marking indicates that the term should be coded inside
** a conditional such that is only evaluated on the second pass of a
** LIKE-optimization loop, when scanning BLOBs instead of strings.
*/
static void disableTerm(WhereLevel *pLevel, WhereTerm *pTerm){
  int nLoop = 0;
  while( pTerm
      && (pTerm->wtFlags & TERM_CODED)==0
      && (pLevel->iLeftJoin==0 || ExprHasProperty(pTerm->pExpr, EP_FromJoin))
      && (pLevel->notReady & pTerm->prereqAll)==0

} {0 0 0 {SEARCH TABLE t1 USING INDEX i1 (b>? AND b<?)}}
do_eqp_test analyze3-2.3 {
  SELECT count(a) FROM t1 WHERE b LIKE '%a'
} {0 0 0 {SCAN TABLE t1}}

do_test analyze3-2.4 {
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE 'a%' }
} {102 0 100}
do_test analyze3-2.5 {
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE '%a' }
} {999 999 100}

do_test analyze3-2.6 {
  set like "a%"
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like }
} {102 0 100}
do_test analyze3-2.7 {
  set like "%a"
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like }
} {999 999 100}
do_test analyze3-2.8 {
  set like "a"
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like }
} {102 0 0}
do_test analyze3-2.9 {
  set like "ab"
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like }
} {12 0 0}
do_test analyze3-2.10 {
  set like "abc"
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like }
} {3 0 1}
do_test analyze3-2.11 {
  set like "a_c"
  sf_execsql { SELECT count(*) FROM t1 WHERE b LIKE $like }
} {102 0 10}


#-------------------------------------------------------------------------
# This block of tests checks that statements are correctly marked as
# expired when the values bound to any parameters that may affect the 
# query plan are modified.
#

      SELECT a FROM t10 WHERE e LIKE '12%' ORDER BY +a;
    }
  } {12 123 scan 5 like 6}
  do_test like-10.5 {
    count {
      SELECT a FROM t10 WHERE f LIKE '12%' ORDER BY +a;
    }
  } {12 123 scan 4 like 0}
  do_test like-10.6 {
    count {
      SELECT a FROM t10 WHERE a LIKE '12%' ORDER BY +a;
    }
  } {12 123 scan 5 like 6}
  do_test like-10.10 {
    execsql {

      SELECT a FROM t10b WHERE e GLOB '12*' ORDER BY +a;
    }
  } {12 123 scan 5 like 6}
  do_test like-10.14 {
    count {
      SELECT a FROM t10b WHERE f GLOB '12*' ORDER BY +a;
    }
  } {12 123 scan 4 like 0}
  do_test like-10.15 {
    count {
      SELECT a FROM t10b WHERE a GLOB '12*' ORDER BY +a;
    }
  } {12 123 scan 5 like 6}
}

# 2015-03-06
#
# 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 LIKE and GLOB operators and
# in particular the optimizations that occur to help those operators
# run faster and that those optimizations work correctly when there
# are both strings and blobs being tested.
#
# Ticket 05f43be8fdda9fbd948d374319b99b054140bc36 shows that the following
# SQL was not working correctly:
#
#     CREATE TABLE t1(x TEXT UNIQUE COLLATE nocase);
#     INSERT INTO t1(x) VALUES(x'616263');
#     SELECT 'query-1', x FROM t1 WHERE x LIKE 'a%';
#     SELECT 'query-2', x FROM t1 WHERE +x LIKE 'a%';
#
# This script verifies that it works right now.
#

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

do_execsql_test like3-1.1 {
  PRAGMA encoding=UTF8;
  CREATE TABLE t1(a,b TEXT COLLATE nocase);
  INSERT INTO t1(a,b)
     VALUES(1,'abc'),
           (2,'ABX'),
           (3,'BCD'),
           (4,x'616263'),
           (5,x'414258'),
           (6,x'424344');
  CREATE INDEX t1ba ON t1(b,a);

  SELECT a, b FROM t1 WHERE b LIKE 'aB%' ORDER BY +a;
} {1 abc 2 ABX 4 abc 5 ABX}
do_execsql_test like3-1.2 {
  SELECT a, b FROM t1 WHERE +b LIKE 'aB%' ORDER BY +a;
} {1 abc 2 ABX 4 abc 5 ABX}

do_execsql_test like3-1.3 {
  CREATE TABLE t2(a, b TEXT);
  INSERT INTO t2 SELECT a, b FROM t1;
  CREATE INDEX t2ba ON t2(b,a);
  SELECT a, b FROM t2 WHERE b GLOB 'ab*' ORDER BY +a;
} {1 abc 4 abc}
do_execsql_test like3-1.4 {
  SELECT a, b FROM t2 WHERE +b GLOB 'ab*' ORDER BY +a;
} {1 abc 4 abc}

finish_test

do_test where8-1.3 { 
  execsql_status2 { SELECT c FROM t1 WHERE a > 8 OR b = 'two' }
} {IX X II 0 0 6}

do_test where8-1.4 { 
  execsql_status2 { SELECT c FROM t1 WHERE a > 8 OR b GLOB 't*' }
} {IX X III II 0 0 10}

do_test where8-1.5 { 
  execsql_status2 { SELECT c FROM t1 WHERE a > 8 OR b GLOB 'f*' }
} {IX X V IV 0 0 10}

do_test where8-1.6 { 
  execsql_status { SELECT c FROM t1 WHERE a = 1 OR b = 'three' ORDER BY rowid }
} {I III 0 1}

do_test where8-1.7 { 
  execsql_status { SELECT c FROM t1 WHERE a = 1 OR b = 'three' ORDER BY a }