On 2010-11-13 5:36 PM +0200, Clark C. Evans wrote:
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;
I'm assuming you forgot to give the tables aliases:
WITH t AS (UPDATE foo SET access = access + 1 RETURNING *)
SELECT x.access, y.access
FROM t x CROSS JOIN t y;
This would return n * n rows with values (1,1) where n is the number of
rows in foo when the snapshot was taken. I.e. every row in foo would
now have access=1. I'm also ignoring the possibility that someone
modified the table between those two queries.
Regards,
Marko Tiikkaja
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