rs.next() not working

[ALaxmi Shankaran]

when i use any simple query like
select quantity from purchaseorder where ponumber=somenumber
then if record is not present then it returns false for if(rs.next()) which is correct
but when i am using the query as
select max(quantity) from purchaseorder where ponumber=somenumber
then even though no records presents then also returns true for if(rs.next()) why it is so?

[Paul Sturrock]

SQL functions always return something (even if that something is null). So select quantity from an empty table will give you an empty resultset, but select Max(quantity) from the same table will give you a result set with one row containing the result of the max() function (which might be 0, might be empty or might be "null" depending on your DB).