Tom Lane schrieb:
At least for me this is surprising!
Why do you find it surprising? Per spec, the SELECT output list is not
evaluated at rows that fail the WHERE clause. This must be so; consider
examples like
SELECT 1/x FROM t WHERE x <> 0;
Of ocurse!
I think what you need is three levels of nested SELECT, with the
nextval() done in the middle level, and probably an "OFFSET 0" in the
middle one to keep Postgres from collapsing the top and middle together.
For the archves.
This works:
DROP SEQUENCE IF EXISTS s;
CREATE TEMPORARY SEQUENCE s;
SELECT * FROM
(
SELECT
nextval('s') AS num,
tablename AS name
FROM
(
SELECT
tablename
FROM
pg_tables
ORDER BY tablename
) AS t
OFFSET 0
) AS ranked
WHERE
ranked.name = 'pg_am'
Thanks a lot!
richard
---------------------------(end of broadcast)---------------------------
TIP 2: Don't 'kill -9' the postmaster
