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Overview
| Comment: | The docs promise the in "x BETWEEN y AND z" the x expression is only evaluated once. That is no longer true, and so some tests are failing. This needs to be fixed before merging to trunk. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | rowvalue |
| Files: | files | file ages | folders |
| SHA1: |
e50d264fdc2f08d19202c68f73f18df3 |
| User & Date: | drh 2016-08-20 22:49:28.330 |
Context
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2016-08-22
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| 00:48 | Reinstate the mechanism in BETWEEN that avoids evaluating the first expression more than once, but fix the affinity extractor so that it works with this mechanism. The de-duplication of the first expression still does not work for vector expressions, though. (check-in: 2f39987f21 user: drh tags: rowvalue) | |
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2016-08-20
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| 22:49 | The docs promise the in "x BETWEEN y AND z" the x expression is only evaluated once. That is no longer true, and so some tests are failing. This needs to be fixed before merging to trunk. (check-in: e50d264fdc user: drh tags: rowvalue) | |
| 21:11 | Further comment enhancements. No changes to code. (check-in: d4562a9e7b user: drh tags: rowvalue) | |
Changes
Changes to src/expr.c.
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4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 | ** ** The above is equivalent to ** ** x>=y AND x<=z ** ** Code it as such, taking care to do the common subexpression ** elimination of x. */ static void exprCodeBetween( Parse *pParse, /* Parsing and code generating context */ Expr *pExpr, /* The BETWEEN expression */ | > > > > > > > > | | | | > < < < | | < < < | | | < | < | < | < | | | 4060 4061 4062 4063 4064 4065 4066 4067 4068 4069 4070 4071 4072 4073 4074 4075 4076 4077 4078 4079 4080 4081 4082 4083 4084 4085 4086 4087 4088 4089 4090 4091 4092 4093 4094 4095 4096 4097 4098 4099 4100 4101 4102 4103 4104 4105 4106 4107 4108 4109 4110 4111 4112 4113 4114 4115 4116 4117 4118 4119 4120 4121 |
**
** The above is equivalent to
**
** x>=y AND x<=z
**
** Code it as such, taking care to do the common subexpression
** elimination of x.
**
** The xJumpIf parameter determines details:
**
** NULL: Store the boolean result in reg[dest]
** sqlite3ExprIfTrue: Jump to dest if true
** sqlite3ExprIfFalse: Jump to dest if false
**
** The jumpIfNull parameter is ignored if xJumpIf is NULL.
*/
static void exprCodeBetween(
Parse *pParse, /* Parsing and code generating context */
Expr *pExpr, /* The BETWEEN expression */
int dest, /* Jump destination or storage location */
void (*xJump)(Parse*,Expr*,int,int), /* Action to take */
int jumpIfNull /* Take the jump if the BETWEEN is NULL */
){
Expr exprAnd; /* The AND operator in x>=y AND x<=z */
Expr compLeft; /* The x>=y term */
Expr compRight; /* The x<=z term */
assert( xJump==0 || xJump==sqlite3ExprIfTrue || xJump==sqlite3ExprIfFalse );
assert( !ExprHasProperty(pExpr, EP_xIsSelect) );
memset(&compLeft, 0, sizeof(Expr));
memset(&compRight, 0, sizeof(Expr));
memset(&exprAnd, 0, sizeof(Expr));
exprAnd.op = TK_AND;
exprAnd.pLeft = &compLeft;
exprAnd.pRight = &compRight;
compLeft.op = TK_GE;
compLeft.pLeft = pExpr->pLeft;
compLeft.pRight = pExpr->x.pList->a[0].pExpr;
compRight.op = TK_LE;
compRight.pLeft = pExpr->pLeft;
compRight.pRight = pExpr->x.pList->a[1].pExpr;
if( xJump ){
xJump(pParse, &exprAnd, dest, jumpIfNull);
}else{
/*exprX.flags |= EP_FromJoin;*/
sqlite3ExprCodeTarget(pParse, &exprAnd, dest);
}
/* Ensure adequate test coverage */
testcase( xJump==sqlite3ExprIfTrue && jumpIfNull==0 );
testcase( xJump==sqlite3ExprIfTrue && jumpIfNull!=0 );
testcase( xJump==sqlite3ExprIfFalse && jumpIfNull==0 );
testcase( xJump==sqlite3ExprIfFalse && jumpIfNull!=0 );
testcase( xJump==0 );
}
/*
** Generate code for a boolean expression such that a jump is made
** to the label "dest" if the expression is true but execution
** continues straight thru if the expression is false.
**
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