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Fix UNION/INTERSECT/EXCEPT so that when two inputs being merged have

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same data type and same typmod, we show that typmod as the output
typmod, rather than generic -1.  This responds to several complaints
over the past few years about UNIONs unexpectedly dropping length or
precision info.
This commit is contained in:
Tom Lane
2006-08-10 02:36:29 +00:00
parent e860e746e1
commit 0ee26100b6
11 changed files with 79 additions and 35 deletions
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74
src/backend/parser/analyze.c
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@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.343 2006/08/02 14:14:22 tgl Exp $
* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.344 2006/08/10 02:36:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -131,7 +131,8 @@ static void transformFKConstraints(ParseState *pstate,
bool skipValidation,
bool isAddConstraint);
static void applyColumnNames(List *dst, List *src);
static List *getSetColTypes(ParseState *pstate, Node *node);
static void getSetColTypes(ParseState *pstate, Node *node,
List **colTypes, List **colTypmods);
static void transformLockingClause(Query *qry, LockingClause *lc);
static void transformConstraintAttrs(List *constraintList);
static void transformColumnType(ParseState *pstate, ColumnDef *column);
@ -2312,7 +2313,8 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
List *lockingClause;
Node *node;
ListCell *left_tlist,
*dtlist,
*lct,
*lcm,
*l;
List *targetvars,
*targetnames,
@ -2395,9 +2397,10 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
targetnames = NIL;
left_tlist = list_head(leftmostQuery->targetList);
foreach(dtlist, sostmt->colTypes)
forboth(lct, sostmt->colTypes, lcm, sostmt->colTypmods)
{
Oid colType = lfirst_oid(dtlist);
Oid colType = lfirst_oid(lct);
int32 colTypmod = lfirst_int(lcm);
TargetEntry *lefttle = (TargetEntry *) lfirst(left_tlist);
char *colName;
TargetEntry *tle;
@ -2408,7 +2411,7 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
expr = (Expr *) makeVar(leftmostRTI,
lefttle->resno,
colType,
-1,
colTypmod,
0);
tle = makeTargetEntry(expr,
(AttrNumber) pstate->p_next_resno++,
@ -2609,8 +2612,12 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
SetOperationStmt *op = makeNode(SetOperationStmt);
List *lcoltypes;
List *rcoltypes;
ListCell *l;
ListCell *r;
List *lcoltypmods;
List *rcoltypmods;
ListCell *lct;
ListCell *rct;
ListCell *lcm;
ListCell *rcm;
const char *context;
context = (stmt->op == SETOP_UNION ? "UNION" :
@ -2630,24 +2637,43 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
* Verify that the two children have the same number of non-junk
* columns, and determine the types of the merged output columns.
*/
lcoltypes = getSetColTypes(pstate, op->larg);
rcoltypes = getSetColTypes(pstate, op->rarg);
getSetColTypes(pstate, op->larg, &lcoltypes, &lcoltypmods);
getSetColTypes(pstate, op->rarg, &rcoltypes, &rcoltypmods);
if (list_length(lcoltypes) != list_length(rcoltypes))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("each %s query must have the same number of columns",
context)));
Assert(list_length(lcoltypes) == list_length(lcoltypmods));
Assert(list_length(rcoltypes) == list_length(rcoltypmods));
op->colTypes = NIL;
forboth(l, lcoltypes, r, rcoltypes)
op->colTypmods = NIL;
/* don't have a "foreach4", so chase two of the lists by hand */
lcm = list_head(lcoltypmods);
rcm = list_head(rcoltypmods);
forboth(lct, lcoltypes, rct, rcoltypes)
{
Oid lcoltype = lfirst_oid(l);
Oid rcoltype = lfirst_oid(r);
Oid lcoltype = lfirst_oid(lct);
Oid rcoltype = lfirst_oid(rct);
int32 lcoltypmod = lfirst_int(lcm);
int32 rcoltypmod = lfirst_int(rcm);
Oid rescoltype;
int32 rescoltypmod;
/* select common type, same as CASE et al */
rescoltype = select_common_type(list_make2_oid(lcoltype, rcoltype),
context);
/* if same type and same typmod, use typmod; else default */
if (lcoltype == rcoltype && lcoltypmod == rcoltypmod)
rescoltypmod = lcoltypmod;
else
rescoltypmod = -1;
op->colTypes = lappend_oid(op->colTypes, rescoltype);
op->colTypmods = lappend_int(op->colTypmods, rescoltypmod);
lcm = lnext(lcm);
rcm = lnext(rcm);
}
return (Node *) op;
@ -2656,17 +2682,19 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
/*
* getSetColTypes
* Get output column types of an (already transformed) set-op node
* Get output column types/typmods of an (already transformed) set-op node
*/
static List *
getSetColTypes(ParseState *pstate, Node *node)
static void
getSetColTypes(ParseState *pstate, Node *node,
List **colTypes, List **colTypmods)
{
*colTypes = NIL;
*colTypmods = NIL;
if (IsA(node, RangeTblRef))
{
RangeTblRef *rtr = (RangeTblRef *) node;
RangeTblEntry *rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
Query *selectQuery = rte->subquery;
List *result = NIL;
ListCell *tl;
Assert(selectQuery != NULL);
@ -2677,9 +2705,11 @@ getSetColTypes(ParseState *pstate, Node *node)
if (tle->resjunk)
continue;
result = lappend_oid(result, exprType((Node *) tle->expr));
*colTypes = lappend_oid(*colTypes,
exprType((Node *) tle->expr));
*colTypmods = lappend_int(*colTypmods,
exprTypmod((Node *) tle->expr));
}
return result;
}
else if (IsA(node, SetOperationStmt))
{
@ -2687,13 +2717,11 @@ getSetColTypes(ParseState *pstate, Node *node)
/* Result already computed during transformation of node */
Assert(op->colTypes != NIL);
return op->colTypes;
*colTypes = op->colTypes;
*colTypmods = op->colTypmods;
}
else
{
elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
return NIL; /* keep compiler quiet */
}
}
/* Attach column names from a ColumnDef list to a TargetEntry list */