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Overview
| Comment: | Improvements to the sqlite3ExprImpliesNonNullRow() theorem prover. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
3fde627616030ca0de87169467e2e453 |
| User & Date: | drh 2019-04-01 19:42:42 |
Context
|
2019-04-02
| ||
| 00:28 | Add the sqlite3_value_frombind() interface. Use that interface to improve fts3_tokenizer(). check-in: b3f2c320 user: drh tags: trunk | |
|
2019-04-01
| ||
| 19:42 | Improvements to the sqlite3ExprImpliesNonNullRow() theorem prover. check-in: 3fde6276 user: drh tags: trunk | |
| 18:43 | Add a test case to cover a missed VDBE branch generated by window.c. check-in: b36813d6 user: dan tags: trunk | |
Changes
Changes to src/expr.c.
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** an ordinary JOIN. The p argument is the WHERE clause. If the WHERE
** clause requires that some column of the right table of the LEFT JOIN
** be non-NULL, then the LEFT JOIN can be safely converted into an
** ordinary join.
*/
int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab){
Walker w;
w.xExprCallback = impliesNotNullRow;
w.xSelectCallback = 0;
w.xSelectCallback2 = 0;
w.eCode = 0;
w.u.iCur = iTab;
sqlite3WalkExpr(&w, p);
return w.eCode;
|
> > > > > > > > > > > |
5028 5029 5030 5031 5032 5033 5034 5035 5036 5037 5038 5039 5040 5041 5042 5043 5044 5045 5046 5047 5048 5049 5050 5051 5052 |
** an ordinary JOIN. The p argument is the WHERE clause. If the WHERE
** clause requires that some column of the right table of the LEFT JOIN
** be non-NULL, then the LEFT JOIN can be safely converted into an
** ordinary join.
*/
int sqlite3ExprImpliesNonNullRow(Expr *p, int iTab){
Walker w;
p = sqlite3ExprSkipCollate(p);
while( p ){
if( p->op==TK_NOTNULL ){
p = p->pLeft;
}else if( p->op==TK_AND ){
if( sqlite3ExprImpliesNonNullRow(p->pLeft, iTab) ) return 1;
p = p->pRight;
}else{
break;
}
}
w.xExprCallback = impliesNotNullRow;
w.xSelectCallback = 0;
w.xSelectCallback2 = 0;
w.eCode = 0;
w.u.iCur = iTab;
sqlite3WalkExpr(&w, p);
return w.eCode;
|