lysander_fb wrote:

> I was trying a left outer join of both tables, and filtering for NULL
> values on the right (bills) side. But I did not manage to get the
> syntax correct.

select t1.orderno, t1.ordertitle
from orders t1
left join bills t2 on t2.bill_reference = t1.orderno
where t2.bill_id is null

should work and is probably faster than your approach (afaik "count" is
a performance-killer), but you should test that yourself.

> Thanks for ideas,
> André

Magnus