I've been retrieving values using ADO, and setting those
values to a variable MTDSALES (for month to date sales)
which is declared as double.

The problem is that when the retrieved value is Null
I get an error "Invalid Use of Null". Any ideas on how to
handle this situation efficiently?

I could send all retrieved values to a function which
checks for the NUll case and then sends back 0.00 if it is
Null but I'm not sure if this the best way to go about it.

Thanks in advance.