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