Re: Problems using count() with a join - trying to format

Hi Igor,

wouldn't

select g_name,count(*),sum(u_act) from g1 join users using(g_id)
group by g_name

do the job?

/Ulrich

> Result can be obtained by:
>
> SELECT g1.g_name,
> (select count(*) from users u1 where g1.g_id = u1.g_id) as users_count,
> (select count(*) from users u2 where g1.g_id = u2.g_id and u_act = 1) as
> Active_users_count
> FROM groups g1
>
> Regards,
>
>
> Igor
>
>
> "Igor Kryltsov" <kryltsov@yahoo.com> wrote in message
> news:cfrqra$1m4s$1@news.hub.org...
>
>>Hi,
>>
>>
>>I am using slightly modified example posted by Doug Younger and answered
>
> by
>
>>Tom Lane :)
>>(http://archives.postgresql.org/pgsql-sql/1999-08/msg00159.php)
>>
>>I have the following 2 tables:
>>
>>Table groups:
>>  g_id     int4
>>  g_name   text
>>
>>Table users:
>>  u_id     int4
>>  g_id     int4  u_act    int4  0 - value means "Inactive" and 1 - value
>>means "Active" (used instead of boolean type for DB interoperability :) )
>>What I want is to get a count of users in each group with count of active
>>users in each group, even if there are no users in the group.
>>
>>
>>This example gives a count of users in each group:
>>SELECT t1.g_name,count(t2.g_id) as users_count
>>  FROM groups t1,users t2
>>  WHERE t1.g_id = t2.g_id
>>  GROUP BY t1.g_name;
>>
>>If you can help to modify it to output --> g_name, users_count,
>>active_users_count
>>So it could be:
>>Group_A    |    89    |    34
>>Group_B    |    75    |    75
>>Group_C    |    25    |    0  <-- all users are inactive here
>>Group_D    |    0     |    0 <---- Assume that this is a result of UNION
>>which will add groups without employees
>>
>>
>>
>>Thank you,
>>
>>Igor
>>
>>
>
>
>
>
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