diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/vdbe.c | 6 | ||||
| -rw-r--r-- | src/where.c | 19 |
2 files changed, 17 insertions, 8 deletions
diff --git a/src/vdbe.c b/src/vdbe.c index 0c9a67e56..6adea6796 100644 --- a/src/vdbe.c +++ b/src/vdbe.c @@ -1053,9 +1053,9 @@ case OP_String8: { /* same as TK_STRING, out2-prerelease */ ** 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 convert to BLOB. The content is -** the same string text, it is merely interpreted as a BLOB as if it -** had been CAST. +** 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 ); diff --git a/src/where.c b/src/where.c index 24c384347..e79e7d33b 100644 --- a/src/where.c +++ b/src/where.c @@ -1109,7 +1109,7 @@ static void exprAnalyze( 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; /* LIKE/GLOB distinguishes case */ + 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 */ @@ -1247,12 +1247,15 @@ static void exprAnalyze( /* 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 + ** A like pattern of the form "x LIKE 'aBc%'" is changed into constraints ** - ** x>='abc' AND x<'abd' AND x LIKE 'abc%' + ** x>='ABC' AND x<'abd' AND x LIKE 'aBc%' ** ** The last character of the prefix "abc" is incremented to form the - ** termination condition "abd". + ** 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) @@ -1266,7 +1269,6 @@ static void exprAnalyze( Token sCollSeqName; /* Name of collating sequence */ const u16 wtFlags = TERM_LIKEOPT | TERM_VIRTUAL | TERM_DYNAMIC; - pTerm->wtFlags |= TERM_LIKE; pLeft = pExpr->x.pList->a[1].pExpr; pStr2 = sqlite3ExprDup(db, pStr1, 0); @@ -1277,6 +1279,7 @@ static void exprAnalyze( 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); @@ -2502,6 +2505,12 @@ static int whereInScanEst( ** 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; |