Re: Check for an empty result

In response to Eus :
> Hi Ho!
>
> Is there a way to check whether or not a subquery returns an empty result set?

You can use EXISTS for that:

-- empty result
test=*# select * from (select 1 where 1=2) foo;
 ?column?
----------
(0 rows)

-- check if a result exists
test=*# select exists(select * from (select 1 where 1=2) foo);
 ?column?
----------
 f
(1 row)

test=*# select exists(select * from (select 1 where 1=1) foo);
 ?column?
----------
 t
(1 row)

Regards, Andreas
--
Andreas Kretschmer
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