BUG #4956: Array Construct array() returning blank result
The following bug has been logged online:
Bug reference: 4956
Logged by: Niranjan Pandit
Email address: niranjan81@gmail.com
PostgreSQL version: 8.4
Operating system: Windows Vista Ultimate
Description: Array Construct array() returning blank result
Details:
Hi,
I simply wanted to accumulate result of a subquery in to an array, so I did
select array(select userid from user where <some condition>);
Only when the condition gets evaluated to true with at least 2 columns with
varying values the array gets constructed, in all other cases what we get is
a complete blank output. the label of the result is as usual as ?column? but
there is absolutely nothing in the cell below the label.
I am sorry if I am repeating something already known to mankind :-) but
after a lot search I could not get anything on it on the net.
Thanks in advance.
Best Wishes.
"Niranjan Pandit" <niranjan81@gmail.com> writes:
Only when the condition gets evaluated to true with at least 2 columns with
varying values the array gets constructed, in all other cases what we get is
a complete blank output. the label of the result is as usual as ?column? but
there is absolutely nothing in the cell below the label.
Hmm, seems to work for me:
regression=# select array(select unique1 from tenk1 where unique2 < 2);
?column?
-------------
{8800,1891}
(1 row)
regression=# select array(select unique1 from tenk1 where unique2 < 1);
?column?
----------
{8800}
(1 row)
regression=# select array(select unique1 from tenk1 where unique2 < 0);
?column?
----------
{}
(1 row)
Pre-8.3 PG releases would return NULL instead of an empty array in the
last case, but 8,4 should not. If you're seeing differently, we'll
need a self-contained test case.
regards, tom lane