[Zope] dtml-if based on result from zsql method

I try to write zsql method with behaviour based on result from another zsql method (simple select count(x) from table where x=...). If there are records for x i want to do something, but if not, something else. I tried to write something like that (x is an parameter of both zsql methods): <dtml-call zsql_count> <dtml if expr=""> something <dtml-else> something else </dtml-if> I dont know what to write as <dtml-if> expression. Mariusz