Question

I wrote a query. this query sum fields from 2 different table. And grouped by main table id field. But second left outer join is not grouped and giving me different results.

SELECT s.*,
       f.firma_adi,
       sum(sd.fiyat) AS konak,
       sum(ss.fiyat) AS sponsor
FROM   fuar_sozlesme1 s
       INNER JOIN fuar_firma_2012 f
         ON ( s.cari = f.cari )
       LEFT OUTER JOIN fuar_sozlesme1_detay sd
         ON ( sd.sozlesme_id = s.id )
       LEFT OUTER JOIN fuar_sozlesme1_sponsor ss
         ON ( ss.sozlesme_id = s.id )
GROUP  BY s.id
ORDER  BY s.id DESC 

I know, it is really complicated but I’m stucking on this issue.
My question is: why second left outer join is not correctly sum of field . If I remove second left outer join or first, everything is normal.

Answer 1

The problem is that you have multiple dimensions on your data, and the number of rows is multiplying beyond what you expect. I would suggest that you run the query for one id, without the group by, to see what rows the join is producing.

One way to fix this is by using correlated subqueries:

select s.*, f.firma_adi,
       (select SUM(sd.fiyat)
        from fuar_sozlesme1_detay fd
        where sd.sozlesme_id = s.id
       ) as konak,
       (select SUM(ss.fiyat)
        from fuar_sozlesme1_sponsor ss
        where (ss.sozlesme_id = s.id)
       ) as sponsor
from fuar_sozlesme1 s inner join
     fuar_firma_2012 f
     on (s.cari = f.cari)
order by s.id DESC

By the way, you appear to by using MySQL (because your query is not parsable in any other dialect). You should tag your questions with the version of the database you are using.