Hi Cetin,
Thanks. That's essentially what I ended up doing - although mine might have been more limited in scope (would have to try your query below to see what it covers off).

Albert

>Can't you simply check for such cases with an SQL like:
>
>

>select * from myTable t1 ;
>where exists (select * from myTable t2 ;
>  where t1.Company_id = t2.ParentColId and t1.ParentColId = t2.Company_Id)
>