Subselect question

Hi,

I have some trouble with subselects. (Version 6.3).

If I try

Select name, address from costumers where cod_costumer  in (
Select cod_costumer from logins where total_usage > 0);

It take lots of time (really I din't wait till the end).

But if I manualy split in
Select cod_costumer from logins where total_usage > 0;
getting
( 1,  9, 15, 18 , 40)
and then use
Select name, address from costumers where cod_costumer  in ( 1,  9,
15, 18 , 40);

All is OK.

Is this type of subselect suported ?

Thanks
 Giovanni Floridia