Horton

Re: wCTE behaviour

Clark C. Evans <cce@clarkevans.com>

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From: "Clark C. Evans" <cce@clarkevans.com>
To: "Marko Tiikkaja" <marko.tiikkaja@cs.helsinki.fi>, "Tom Lane" <tgl@sss.pgh.pa.us>
Cc: "David Fetter" <david@fetter.org>, "Yeb Havinga" <yebhavinga@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2010-11-13T15:36:21Z
Lists: pgsql-hackers 
On Sat, 13 Nov 2010 17:23 +0200, "Marko Tiikkaja" wrote:
> So these queries would behave differently?
> 
> WITH t AS (DELETE FROM foo RETURNING *)
> SELECT 1 WHERE false;
>
> WITH t AS (DELETE FROM foo RETURNING *)
> SELECT 1 FROM t LIMIT 0;

I'm still trying to wrap my head around this
new mechanism.  What would this return?

UPDATE foo SET access = 0;

WITH t AS (UPDATE foo SET access = access + 1 RETURNING *)
SELECT x.access, y.access
 FROM t CROSS JOIN t;