On Mar 5, 2009, at 11:17 AM, Richard Greenwood wrote:
Hello pgsql listers,
I've got a problem that is similar to, but I don't think identical to,
a cross tab query. My data looks like:
ID | CAT
1 | A
1 | B
2 | A
2 | C
So for each ID there may be many CAT (categories).
The client wants it to look like:
ID | CATS
1 | A,B
2 | A,C
Where each ID is unique in the results, and the CAT values are
concatenated with a comma separator.
There are about 100 unique CAT values. They only way I can see to do
it is programatically with a for loop. But before I do that I wanted
to bounce it off the fine minds that inhabit this list.
Sounds like a job for array_accum(), which you can find mentioned
at http://www.postgresql.org/docs/8.3/interactive/xaggr.html
select id, array_to_string(array_accum(cat), ',') from table group by
id;
There'll be a built-in array_agg() in 8.4, I think.
Cheers,
Steve
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
