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Fix WITH attached to a nested set operation (UNION/INTERSECT/EXCEPT).

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Parse analysis neglected to cover the case of a WITH clause attached to an
intermediate-level set operation; it only handled WITH at the top level
or WITH attached to a leaf-level SELECT.  Per report from Adam Mackler.

In HEAD, I rearranged the order of SelectStmt's fields to put withClause
with the other fields that can appear on non-leaf SelectStmts.  In back
branches, leave it alone to avoid a possible ABI break for third-party
code.

Back-patch to 8.4 where WITH support was added.
This commit is contained in:
Tom Lane 2012-07-31 17:56:37 -04:00
parent 706f792fc5
commit ae47eb112f
4 changed files with 115 additions and 13 deletions
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27
src/backend/parser/analyze.c
View File

@ -1144,6 +1144,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
Node *limitOffset;
Node *limitCount;
List *lockingClause;
WithClause *withClause;
Node *node;
ListCell *left_tlist,
*lct,
@ -1159,13 +1160,6 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
qry->commandType = CMD_SELECT;
/* process the WITH clause independently of all else */
if (stmt->withClause)
{
qry->hasRecursive = stmt->withClause->recursive;
qry->cteList = transformWithClause(pstate, stmt->withClause);
}
/*
* Find leftmost leaf SelectStmt; extract the one-time-only items from it
* and from the top-level node.
@ -1193,11 +1187,13 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
limitOffset = stmt->limitOffset;
limitCount = stmt->limitCount;
lockingClause = stmt->lockingClause;
withClause = stmt->withClause;
stmt->sortClause = NIL;
stmt->limitOffset = NULL;
stmt->limitCount = NULL;
stmt->lockingClause = NIL;
stmt->withClause = NULL;
/* We don't support FOR UPDATE/SHARE with set ops at the moment. */
if (lockingClause)
@ -1205,6 +1201,13 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
/* Process the WITH clause independently of all else */
if (withClause)
{
qry->hasRecursive = withClause->recursive;
qry->cteList = transformWithClause(pstate, withClause);
}
/*
* Recursively transform the components of the tree.
*/
@ -1394,10 +1397,10 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt,
errmsg("SELECT FOR UPDATE/SHARE is not allowed with UNION/INTERSECT/EXCEPT")));
/*
* If an internal node of a set-op tree has ORDER BY, LIMIT, or FOR UPDATE
* clauses attached, we need to treat it like a leaf node to generate an
* independent sub-Query tree. Otherwise, it can be represented by a
* SetOperationStmt node underneath the parent Query.
* If an internal node of a set-op tree has ORDER BY, LIMIT, FOR UPDATE,
* or WITH clauses attached, we need to treat it like a leaf node to
* generate an independent sub-Query tree. Otherwise, it can be
* represented by a SetOperationStmt node underneath the parent Query.
*/
if (stmt->op == SETOP_NONE)
{
@ -1408,7 +1411,7 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt,
{
Assert(stmt->larg != NULL && stmt->rarg != NULL);
if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
stmt->lockingClause)
stmt->lockingClause || stmt->withClause)
isLeaf = true;
else
isLeaf = false;

15
src/backend/parser/parse_cte.c
View File

@ -627,6 +627,18 @@ checkWellFormedRecursion(CteState *cstate)
if (cstate->selfrefcount != 1) /* shouldn't happen */
elog(ERROR, "missing recursive reference");
/* WITH mustn't contain self-reference, either */
if (stmt->withClause)
{
cstate->curitem = i;
cstate->innerwiths = NIL;
cstate->selfrefcount = 0;
cstate->context = RECURSION_SUBLINK;
checkWellFormedRecursionWalker((Node *) stmt->withClause->ctes,
cstate);
Assert(cstate->innerwiths == NIL);
}
/*
* Disallow ORDER BY and similar decoration atop the UNION. These
* don't make sense because it's impossible to figure out what they
@ -882,7 +894,7 @@ checkWellFormedSelectStmt(SelectStmt *stmt, CteState *cstate)
cstate);
checkWellFormedRecursionWalker((Node *) stmt->lockingClause,
cstate);
break;
/* stmt->withClause is intentionally ignored here */
break;
case SETOP_EXCEPT:
if (stmt->all)
@ -901,6 +913,7 @@ checkWellFormedSelectStmt(SelectStmt *stmt, CteState *cstate)
cstate);
checkWellFormedRecursionWalker((Node *) stmt->lockingClause,
cstate);
/* stmt->withClause is intentionally ignored here */
break;
default:
elog(ERROR, "unrecognized set op: %d",

51
src/test/regress/expected/with.out
View File

@ -1026,3 +1026,54 @@ SELECT * FROM t;
10
(55 rows)
--
-- test WITH attached to intermediate-level set operation
--
WITH outermost(x) AS (
SELECT 1
UNION (WITH innermost as (SELECT 2)
SELECT * FROM innermost
UNION SELECT 3)
)
SELECT * FROM outermost;
x
---
1
2
3
(3 rows)
WITH outermost(x) AS (
SELECT 1
UNION (WITH innermost as (SELECT 2)
SELECT * FROM outermost -- fail
UNION SELECT * FROM innermost)
)
SELECT * FROM outermost;
ERROR: relation "outermost" does not exist
LINE 4: SELECT * FROM outermost
^
DETAIL: There is a WITH item named "outermost", but it cannot be referenced from this part of the query.
HINT: Use WITH RECURSIVE, or re-order the WITH items to remove forward references.
WITH RECURSIVE outermost(x) AS (
SELECT 1
UNION (WITH innermost as (SELECT 2)
SELECT * FROM outermost
UNION SELECT * FROM innermost)
)
SELECT * FROM outermost;
x
---
1
2
(2 rows)
WITH RECURSIVE outermost(x) AS (
WITH innermost as (SELECT 2 FROM outermost) -- fail
SELECT * FROM innermost
UNION SELECT * from outermost
)
SELECT * FROM outermost;
ERROR: recursive reference to query "outermost" must not appear within a subquery
LINE 2: WITH innermost as (SELECT 2 FROM outermost)
^

35
src/test/regress/sql/with.sql
View File

@ -500,3 +500,38 @@ WITH RECURSIVE t(j) AS (
SELECT j+1 FROM t WHERE j < 10
)
SELECT * FROM t;
--
-- test WITH attached to intermediate-level set operation
--
WITH outermost(x) AS (
SELECT 1
UNION (WITH innermost as (SELECT 2)
SELECT * FROM innermost
UNION SELECT 3)
)
SELECT * FROM outermost;
WITH outermost(x) AS (
SELECT 1
UNION (WITH innermost as (SELECT 2)
SELECT * FROM outermost -- fail
UNION SELECT * FROM innermost)
)
SELECT * FROM outermost;
WITH RECURSIVE outermost(x) AS (
SELECT 1
UNION (WITH innermost as (SELECT 2)
SELECT * FROM outermost
UNION SELECT * FROM innermost)
)
SELECT * FROM outermost;
WITH RECURSIVE outermost(x) AS (
WITH innermost as (SELECT 2 FROM outermost) -- fail
SELECT * FROM innermost
UNION SELECT * from outermost
)
SELECT * FROM outermost;