Re: need help with query, how to fold select result to array?

In response to Sergey Levchenko :
> eps=# SELECT office_id, serial, commit_date, service_id, meter_id,
> organization_reading, reading FROM meter_readings WHERE office_id =
> 134 AND serial = 27 AND commit_date = '2010-01-11' AND commit_time =
> '13:44:37' AND person_id = 300871;
>
> office_id | serial | commit_date | service_id | meter_id |
> organization_reading | reading
> -----------+--------+-------------+------------+----------+----------------------+---------
> 134 | 27 | 2010-01-11 | 2 | 71629130 |
> 15518 | 0
> 134 | 27 | 2010-01-11 | 2 | 2668722 |
> 616 | 0
> 134 | 27 | 2010-01-11 | 75 | 111029 |
> 9505 | 0
> 134 | 27 | 2010-01-11 | 4 | 019210 |
> 372 | 0
> (4 rows)
>
> How to get ?
> 134 | 27 | 2010-01-11 | 2 | {{71629130, 15518,
> 0}, {2668722, 616, 0}}
> 134 | 27 | 2010-01-11 | 75 | {111029, 9505, 0}
> 134 | 27 | 2010-01-11 | 4 | {019210, 372, 0}
>
> Thanks a lot!

You can use array_agg(since 8.4):

test=# create table bla (id int, value text);
CREATE TABLE
test=*# copy bla from stdin;
Enter data to be copied followed by a newline.
End with a backslash and a period on a line by itself.
>> 1 bla
>> 1 foo
>> 1 bar
>> 2 foobar
>> 2 test
>> \.
test=*# select id, array_agg(value) from bla group by 1 order by 1;
id | array_agg
----+---------------
1 | {bla,foo,bar}
2 | {foobar,test}
(2 rows)

If you don't have 8.4 search the docu for array_accum:
http://www.postgresql.org/docs/8.4/interactive/xaggr.html

Regards, Andreas
--
Andreas Kretschmer
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