Mariusz,

> Have anyone any idea how to optimise this query?
> (firebird 2.1)
>
> select A.id_cust, A.name, count(together.id_cust)
> from A
> left join
> (
> select id_cust from B
> union all
> select id_cust from C
> ) together on together.id_cust=A.id_cust
> group by A.id_cust, A.name
> order by A.name

What are the engine stats for the query?

What PLAN is generated for the query?


Sean