Question

I am trying to eliminate this division by zero error using CASE in my T-SQL SELECT statement. For some reason, I keep getting the error. Here is my logic.

SELECT 
    CASE 
       WHEN tb1.wpf = 0.000 THEN '0.000' 
       ELSE SUM(tb2.weight/tb1.wpf) 
    END AS Average 
FROM Table1 tb1, table2 tb2 
GROUP BY tb1.wpf

I did not include joins and all my logic to keep my question specific to this case. How can I get rid of this error?

Answer 1

The CASE is going to be applied to the aggregate, not individual bits. Try this:

SELECT SUM(Average) FROM (
    SELECT 
            CASE 
               WHEN tb1.wpf = 0 THEN 0
               ELSE tb2.weight / tb1.wpf
            END AS Average 
        FROM Table1 tb1, table2 tb2 
) a