On Tue, 3 Dec 2002, Magnus Naeslund(f) wrote:
> Now convert this query so that it only evaluates the date_part thing
> ONCE:
>
> select t.id, date_part('days',now()-t.stamp) from table_name t where
> date_part('days',now()-t.stamp) > 20;
Something like this could work:
select *
from (select t.id, date_part('days',now()-t.stamp) AS d
from table_name t) AS t1
where t1.d > 20;
That aside I also would like some sort of local names. Something like the
let construct used in many functional languages (not exaclty what you want
above, but still):
let t1 = select * from foo;
t2 = select * from bar;
in select * from t1 natural join t2;
But even though I would like to give name to subexpressions like above, I
still think postgresql should stick to standards as close as possible.
--
/Dennis
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