From: Tom Lane <tgl@sss.pgh.pa.us>
To: Kumar Babu P G <kumar.pulakunta@gmail.com>
cc: pgsql-sql@postgresql.org
Subject: Re: Postgres behavior - Conditional statements
In-reply-to: 
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Comments: In-reply-to Kumar Babu P G <kumar.pulakunta@gmail.com>
 message dated "Mon, 24 Feb 2014 12:07:24 +0530"
Date: Mon, 24 Feb 2014 11:02:30 -0500
Message-ID: <1905.1393257750@sss.pgh.pa.us>
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Kumar Babu P G <kumar.pulakunta@gmail.com> writes:
> Found strange behavior of postgres between 9.1 and 9.2. Can some one
> pointout the reason for the difference in column name of the output between
> the versions?
> postgres=> select case when exists (select 1 from test where a=1) then 0
> else (select b from test where a=2) end;

http://git.postgresql.org/gitweb/?p=postgresql.git&a=commitdiff&h=5ec6b7f1b87f0fa006b8e08a11cd4e99bcb67358

The behavior of CASE didn't change, but the behavior of the sub-select
did.  More simply, 9.1 gives this

regression=# select (select b from test where a=2);    
 ?column? 
----------
         
(1 row)

while 9.2 and up give

regression=# select (select b from test where a=2);
 b 
---
  
(1 row)


			regards, tom lane


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