Ok,many thanks

but what I´m trying to do is something more complex...

Select aa, bb, 'Neto Gravado'= sum(case  when tligfact.ligfaccalculcode

 in ('5701','5702','5703','5704','5705','5706','5707','5708','5709','5710','5711','5712','5713','171','172','12','16','28','180','5608','7709') then 0

else (tligfact.ligfacunitprice*tligfact.ligfacqtefac) end)

from tligfact where ......

If I put a subquery inside the IN, I get an error, it saids that I cannot put a subquery inside an agregate function !!!, seems to belong from the SUM() ?

So I think that a good idea is to put the result of this subq into a variable. But does not  work.

Ive tried Frank´s , but I get this "Cannot convert parameter '@statement' to ntext/nchar/nvarchar data type expected by procedure. " and now I dont know how to jump this.

waiting for any other idea..........