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Implement CASE expression.

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This commit is contained in:
Thomas G. Lockhart
1998-12-04 15:34:49 +00:00
parent 19740e2fff
commit bedd04a551
17 changed files with 779 additions and 110 deletions
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41
src/backend/optimizer/util/clauses.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.25 1998/11/27 19:52:07 vadim Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.26 1998/12/04 15:34:14 thomas Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -306,6 +306,26 @@ make_andclause(List *andclauses)
return expr;
}
/*****************************************************************************
* CASE clause functions
*****************************************************************************/
/*
* case_clause--
*
* Returns t iff its argument is a 'case' clause: (CASE { expr }).
*
*/
bool
case_clause(Node *clause)
{
return
(clause != NULL &&
nodeTag(clause) == T_CaseExpr);
}
/*****************************************************************************
* *
* *
@@ -540,6 +560,19 @@ fix_opid(Node *clause)
fix_opid((Node *) get_leftop((Expr *) lfirst(lst)));
}
}
else if (case_clause(clause))
{
List *lst;
fix_opid(((CaseExpr *) clause)->defresult);
/* Run through the WHEN clauses... */
foreach(lst, ((CaseExpr *) clause)->args)
{
fix_opid(((CaseWhen *) lfirst(lst))->expr);
fix_opid(((CaseWhen *) lfirst(lst))->result);
}
}
}
@@ -577,13 +610,12 @@ fix_opids(List *clauses)
* returned for the value if it is unknown or null.
* END OF OLD OBSOLETE COMMENT.
* NEW COMMENT:
* when defining rules one of the attibutes of the operator can
* when defining rules one of the attributes of the operator can
* be a Param node (which is supposed to be treated as a constant).
* However as there is no value specified for a parameter until run time
* this routine used to return "" as value, which made 'compute_selec'
* this routine used to return "" as value, which caused 'compute_selec'
* to bomb (because it was expecting a lisp integer and got back a lisp
* string). Now the code returns a plain old good "lispInteger(0)".
*
*/
void
get_relattval(Node *clause,
@@ -787,3 +819,4 @@ CommuteClause(Node *clause)
lfirst(((Expr *) clause)->args) = lsecond(((Expr *) clause)->args);
lsecond(((Expr *) clause)->args) = temp;
}