My Select SUM query returns null. It should return 0

Question

I\'m trying to sum up Customer balances using the following query:

select sum(balance) from mytable where customer = \'john\' 

However, if

Answer 1

Maybe you are thinking of COUNT's behaviours?

COUNT(Field) will return 0 but SUM(Field) returns NULL if there are no matching rows.

You need an ISNULL or COALESCE

COALESCE or ISNULL