On Mon, Oct 03, 2011 at 11:48:45AM +0400, Alexander Pyhalov wrote: > On 10/03/2011 11:19, Achilleas Mantzios wrote: > >Alexander, that's a classic one, > >rewrite your last query as : > > > >SELECT count(employee_id) from employees where employee_id not in > > (select manager_id from employees WHERE manager_id IS NOT NULL); > > > >NULLS semantics are sometimes not so obvious. > > Thanks. > It's confusing, that IN check works as expected, but NOT IN works > this way... If I might plug: http://www.depesz.com/index.php/2008/08/13/nulls-vs-not-in/ Best regards, depesz -- The best thing about modern society is how easy it is to avoid contact with it. http://depesz.com/ -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general