Crystal - Make a blank field zero rather than blank

[mel_flynn]

My crystal report is retrieving values from MS Access via ODBC. Occasionally these (numeric) values will be blank. How can I ensure that a zero is displayed in all such fields?

I have tried:

If {Field} = "" then
0.00

But it keeps saying that it's expecting a numeric value here (at the "")

[brucevde]

If IsNull({Field}) Then 0 Else {Field}