Subquery and where clause ?

Поиск
Список
Период
Сортировка
От Bo Lorentsen
Тема Subquery and where clause ?
Дата
Msg-id 3B83A32D.E75698B5@netgroup.dk
обсуждение исходный текст
Список pgsql-novice
Hi ...

I have been trying to find a way to make several differant table
counters on one request, and therefor tried to use sub queries as my
solution, but I can't make it work and hope someone could help me out
:-(

Lets say I have 3 tables A, B and C and both A and B have a references
to C. I like to make a view that for each C counts the number of
refering A's and B's.

Tables :

CREATE TABLE A (
    INTEGER id,
    INTEGER ref );

CREATE TABLE B (
    INTEGER id,
    INTEGER ref );

CREATE TABLE C (
    INTEGER id );

As I can see it, the SQL would look somthing like this :

    SELECT C.id, A.count, B.count FROM C,
        (SELECT COUNT( A.id ) FROM A WHERE A.ref = C.id) AS A,
        (SELECT COUNT( B.id ) FROM B WHERE B.ref = C.id) AS B;

But the result is the same count for each row :-(

This is off cause a very simple example.

What have I done wrong ?

/BL


В списке pgsql-novice по дате отправления:

Предыдущее
От: Francois Thomas
Дата:
Сообщение: Bad timestamp external representation
Следующее
От: Bo Lorentsen
Дата:
Сообщение: Re: Subquery and where clause ?