Question

Is there a simple built in function in sql2000 that returns 0 or 0.00 if money or a float column is null? Or do I need to build the function myself, and how would I build it? if (isnull(col1)) then 0 else col1?

Answer 1

Yes, the function is called ISNULL, you use it like this:

SELECT ISNULL(columnname, 0.0) AS xyz FROM tablename

You basically specify which value to return in case the first value is null.

Note that ISNULL does not return a boolean value indicating whether the parameter is null or not, instead you pass it 2 parameters and it does the following:

1. If the first argument is non-null, return the value of the first argument
2. Otherwise, return the second argument

You can also use the COALESCE function for this, which takes an unspecified number of parameters, and returns the first non-null argument value back, in the order they’re specified.

In other words:

ISNULL(columnname, 0.0)

and

COALESCE(columnname, 0.0)

behaves the same, but I don’t know if there is a difference in “sargeability” of these two, ie. whether they can use indexes or not.