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The query flattener must add TK_IF_NULL_ROW opcodes on substituted values

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that land on the left operand of a RIGHT JOIN, just as it already does for
the right operand of a LEFT JOIN.

FossilOrigin-Name: 8e02cdf5b1128f5e5b82d93903063415ec312694e5ccdd19e99fa35433f1b68a
This commit is contained in:
drh
2022-04-11 20:15:52 +00:00
parent ec27077c4f
commit c133bab72a
3 changed files with 47 additions and 19 deletions
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12
manifest
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@@ -1,5 +1,5 @@
C New\stest\scases\sadded.
D 2022-04-11T18:54:23.445
C The\squery\sflattener\smust\sadd\sTK_IF_NULL_ROW\sopcodes\son\ssubstituted\svalues\nthat\sland\son\sthe\sleft\soperand\sof\sa\sRIGHT\sJOIN,\sjust\sas\sit\salready\sdoes\sfor\nthe\sright\soperand\sof\sa\sLEFT\sJOIN.
D 2022-04-11T20:15:52.179
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -552,7 +552,7 @@ F src/printf.c 05d8dfd2018bc4fc3ddb8b37eb97ccef7abf985643fa1caebdcf2916ca90fa32
F src/random.c 097dc8b31b8fba5a9aca1697aeb9fd82078ec91be734c16bffda620ced7ab83c
F src/resolve.c 7110fc3b5a4dec5d11559141c1906c4a125349fb602f541b05db3a3d448d4b95
F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
F src/select.c 67d793d9d3008699bc67a079de9eafc0c07d84c12fb867e5b735a79a456a77cb
F src/select.c fdec126045cf441883836756d6d949367e8a2945c53fa6e98d6c51a08d7efc81
F src/shell.c.in eb7f10d5e2c47bd014d92ec5db1def21fcc1ed56ffaaa4ee715b6c37c370b47f
F src/sqlite.h.in 2a35f62185eb5e7ecc64a2f68442b538ce9be74f80f28a00abc24837edcf1c17
F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
@@ -1946,8 +1946,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
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R 1528160c8ffde5ccc7d4edc8311e6b3e
U drh
Z 7ac11620004b739208f6ff19e0608f85
Z 0a6599330cad92a7a73b62ce77e2586b
# Remove this line to create a well-formed Fossil manifest.

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@@ -1 +1 @@
bdd1499c0fa4f8aadf4857a0ccc0d839c250369f29766ebef80330964905e63b
8e02cdf5b1128f5e5b82d93903063415ec312694e5ccdd19e99fa35433f1b68a

52
src/select.c
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@@ -3654,12 +3654,40 @@ static int multiSelectOrderBy(
**
** All references to columns in table iTable are to be replaced by corresponding
** expressions in pEList.
**
** ## About "isOuterJoin":
**
** The isOuterJoin column indicates that the replacement will occur into a
** position in the parent that NULL-able due to an OUTER JOIN. Either the
** target slot in the parent is the right operand of a LEFT JOIN, or one of
** the left operands of a RIGHT JOIN. In either case, we need to potentially
** bypass the substituted expression with OP_IfNullRow.
**
** Suppose the original expression integer constant. Even though the table
** has the nullRow flag set, because the expression is an integer constant,
** it will not be NULLed out. So instead, we insert an OP_IfNullRow opcode
** that checks to see if the nullRow flag is set on the table. If the nullRow
** flag is set, then the value in the register is set to NULL and the original
** expression is bypassed. If the nullRow flag is not set, then the original
** expression runs to populate the register.
**
** Example where this is needed:
**
** CREATE TABLE t1(a INTEGER PRIMARY KEY, b INT);
** CREATE TABLE t2(x INT UNIQUE);
**
** SELECT a,b,m,x FROM t1 LEFT JOIN (SELECT 59 AS m,x FROM t2) ON b=x;
**
** When the subquery on the right side of the LEFT JOIN is flattened, we
** have to add OP_IfNullRow in front of the OP_Integer that implements the
** "m" value of the subquery so that a NULL will be loaded instead of 59
** when processing a non-matched row of the left.
*/
typedef struct SubstContext {
Parse *pParse; /* The parsing context */
int iTable; /* Replace references to this table */
int iNewTable; /* New table number */
int isLeftJoin; /* Add TK_IF_NULL_ROW opcodes on each replacement */
int isOuterJoin; /* Add TK_IF_NULL_ROW opcodes on each replacement */
ExprList *pEList; /* Replacement expressions */
} SubstContext;
@@ -3709,7 +3737,7 @@ static Expr *substExpr(
sqlite3VectorErrorMsg(pSubst->pParse, pCopy);
}else{
sqlite3 *db = pSubst->pParse->db;
if( pSubst->isLeftJoin && pCopy->op!=TK_COLUMN ){
if( pSubst->isOuterJoin && pCopy->op!=TK_COLUMN ){
memset(&ifNullRow, 0, sizeof(ifNullRow));
ifNullRow.op = TK_IF_NULL_ROW;
ifNullRow.pLeft = pCopy;
@@ -3723,7 +3751,7 @@ static Expr *substExpr(
sqlite3ExprDelete(db, pNew);
return pExpr;
}
if( pSubst->isLeftJoin ){
if( pSubst->isOuterJoin ){
ExprSetProperty(pNew, EP_CanBeNull);
}
if( ExprHasProperty(pExpr,EP_FromJoin|EP_InnerJoin) ){
@@ -4105,7 +4133,7 @@ static int flattenSubquery(
SrcList *pSubSrc; /* The FROM clause of the subquery */
int iParent; /* VDBE cursor number of the pSub result set temp table */
int iNewParent = -1;/* Replacement table for iParent */
int isLeftJoin = 0; /* True if pSub is the right side of a LEFT JOIN */
int isOuterJoin = 0; /* True if pSub is the right side of a LEFT JOIN */
int i; /* Loop counter */
Expr *pWhere; /* The WHERE clause */
SrcItem *pSubitem; /* The subquery */
@@ -4178,7 +4206,7 @@ static int flattenSubquery(
**
** See also tickets #306, #350, and #3300.
*/
if( (pSubitem->fg.jointype & JT_OUTER)!=0 ){
if( (pSubitem->fg.jointype & (JT_OUTER|JT_LTORJ))!=0 ){
if( pSubSrc->nSrc>1 /* (3a) */
|| isAgg /* (3b) */
|| IsVirtual(pSubSrc->a[0].pTab) /* (3c) */
@@ -4187,15 +4215,15 @@ static int flattenSubquery(
){
return 0;
}
isLeftJoin = 1;
isOuterJoin = 1;
}
#ifdef SQLITE_EXTRA_IFNULLROW
else if( iFrom>0 && !isAgg ){
/* Setting isLeftJoin to -1 causes OP_IfNullRow opcodes to be generated for
/* Setting isOuterJoin to -1 causes OP_IfNullRow opcodes to be generated for
** every reference to any result column from subquery in a join, even
** though they are not necessary. This will stress-test the OP_IfNullRow
** opcode. */
isLeftJoin = -1;
isOuterJoin = -1;
}
#endif
@@ -4208,7 +4236,7 @@ static int flattenSubquery(
if( pSub->pOrderBy ){
return 0; /* Restriction (20) */
}
if( isAgg || (p->selFlags & SF_Distinct)!=0 || isLeftJoin>0 ){
if( isAgg || (p->selFlags & SF_Distinct)!=0 || isOuterJoin>0 ){
return 0; /* (17d1), (17d2), or (17f) */
}
for(pSub1=pSub; pSub1; pSub1=pSub1->pPrior){
@@ -4454,7 +4482,7 @@ static int flattenSubquery(
}
pWhere = pSub->pWhere;
pSub->pWhere = 0;
if( isLeftJoin>0 ){
if( isOuterJoin>0 ){
sqlite3SetJoinExpr(pWhere, iNewParent, EP_FromJoin);
}
if( pWhere ){
@@ -4469,7 +4497,7 @@ static int flattenSubquery(
x.pParse = pParse;
x.iTable = iParent;
x.iNewTable = iNewParent;
x.isLeftJoin = isLeftJoin;
x.isOuterJoin = isOuterJoin;
x.pEList = pSub->pEList;
substSelect(&x, pParent, 0);
}
@@ -4930,7 +4958,7 @@ static int pushDownWhereTerms(
x.pParse = pParse;
x.iTable = iCursor;
x.iNewTable = iCursor;
x.isLeftJoin = 0;
x.isOuterJoin = 0;
x.pEList = pSubq->pEList;
pNew = substExpr(&x, pNew);
#ifndef SQLITE_OMIT_WINDOWFUNC