sql - Oracle ORA-00979 - "not a GROUP BY expression"

Question

Can anybody please help me with this particular query? I'm having ORA-00979 when trying to run this:

select   t0.title, count (1) as count0, (select   count (1)
      from contract c1, se se1
      where c1.c_id = se1.c_id
      and se1.svc_id = 3
      and se1.deleted = 0
      and c1.deleted = 0
      and c1.c_date between to_date ('07.10.2000', 'dd.mm.yyyy') 
                        and to_date ('22.11.2010', 'dd.mm.yyyy')
      and c1.company = 0
      and c1.tdata.tariff = c0.tdata.tariff
    ) as count1
  from contract c0, se se0, tariff t0
  where c0.c_id = se0.c_id
  and se0.svc_id = 3
  and se0.deleted = 0
  and c0.deleted = 0
  and c0.c_date between to_date ('21.11.2000', 'dd.mm.yyyy') 
                and to_date ('06.01.2011', 'dd.mm.yyyy')
  and c0.company = 0
  and t0.tariff_id = c0.tdata.tariff
  group by t0.title

Answer 1

The problem is your subquery with the select count(1) part. Just because it's got a count in it doesn't actually make it an aggregate. It's still a subquery that will be applied to every row and as you can see it uses the value c0.tdata.tariff which is not part of the group.