Re: Selecting count of details along with details columns

Am 29.09.2005 um 10:30 schrieb Richard Huxton:

> Axel Rau wrote:
>> SELECT T2.T2_name, COUNT(T1.id) AS xx
>> FROM T2, T1
>> WHERE T2.id = T1.fk_t2
>> GROUP BY T2.T2_name
>> HAVING COUNT(T1.id) > 1
>> ORDER BY xx DESC;
>> t2_name | xx
>> ---------+----
>> T2-N2 | 3
>> T2-N3 | 2
>> (2 rows)
>> Adding column t1_name to the result set breaks COUNT(T1.id):
>> SELECT T2.T2_name, T1.T1_name, COUNT(T1.id) AS xx
>> FROM T2, T1
>> WHERE T2.id = T1.fk_t2
>> GROUP BY T2.T2_name, T1.T1_name
>> HAVING COUNT(T1.id) > 1
>> ORDER BY xx DESC;
>> t2_name | t1_name | xx
>> ---------+---------+----
>> (0 rows)
>> How can I do this with pg ?
>
> Do what? You don't say what results you are expecting.
>
> Do you want:
> 1. ALL values of T1_name (in which case what count do you want)?
> 2. The FIRST value of T1_name (in which case what do you mean by
> first)?

#1.:

t2_name | t1_name | count
---------+---------+-------
T2-N2 | T1-CCC | 3
T2-N3 | T1-FFF | 2
T2-N2 | T1-BBB | 3
T2-N2 | T1-DDD | 3
T2-N3 | T1-EEE | 2
(5 rows)

Sorry, for not making this clear.

Thank you for taking the time,

Axel

Axel Rau, Frankfurt, Germany +49-69-951418-0