To: Keith Parks <emkxp01@mtcc.demon.co.uk>
cc: hackers@postgreSQL.org
Subject: Re: [HACKERS] case bug? 
In-reply-to: Your message of Sat, 18 Sep 1999 15:37:17 -0400 
             <20727.937683437@sss.pgh.pa.us> 
Date: Sat, 18 Sep 1999 19:31:27 -0400
Message-ID: <24631.937697487@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
Sender: owner-pgsql-hackers@postgreSQL.org
Precedence: bulk
X-UIDL: f1c99b4f76b4122de93ad6f2400077a0
Status: U

Keith Parks <emkxp01@mtcc.demon.co.uk> writes:
>> Then I tried inserting a NULL into the table, which the
>> case statement then treated as 0 and not null.

> This is a bug: the test expressions i < 0 etc are actually returning
> NULL, but ExecEvalCase is failing to check for a NULL condition result.
> It should treat a NULL as false, I expect, just as WHERE does.

Fixed --- here is the patch for REL6_5.

			regards, tom lane


*** src/backend/executor/execQual.c.orig	Sat Jun 12 15:22:40 1999
--- src/backend/executor/execQual.c	Sat Sep 18 19:28:46 1999
***************
*** 1128,1136 ****
  
  		/*
  		 * if we have a true test, then we return the result, since the
! 		 * case statement is satisfied.
  		 */
! 		if (DatumGetInt32(const_value) != 0)
  		{
  			const_value = ExecEvalExpr((Node *) wclause->result,
  									   econtext,
--- 1128,1137 ----
  
  		/*
  		 * if we have a true test, then we return the result, since the
! 		 * case statement is satisfied.  A NULL result from the test is
! 		 * not considered true.
  		 */
! 		if (DatumGetInt32(const_value) != 0 && ! *isNull)
  		{
  			const_value = ExecEvalExpr((Node *) wclause->result,
  									   econtext,

************