I'm very new to Crystal so my question is probably obvious, but I can't find any simple help on the web.

 

Basically I want to be able calculate a ratio of two fields in a cross tab.  Of the records in my database some of them have a date in column A and some in Column B, I want to work out of the cases with a date in column A what percentage have a date in column B.

 

This is probably a stupid question but I would appreciate a bit of help, thanks.