Java Database Connectivity (JDBC)

hi all,

i am getting some values from my jps page using request.getParameter("") and setting them in query in a servlet for fetching records from oracle db.

i have query something like this:

select product_id from product p, product_types pt where upper(pt.product_name) = nvl(?,upper(pt.product_name)).

if the user on jsp page doesn't input any product name then i m setting "null" explicitly.

but the real issue is how can i set ? to a null (not null string) (just like prepareStatement.setString (1,"abc");) because the query will return all the records if ? is set to null (not "null") and i want exactly that.

any hints???


regards