<chuckling>
You failed to mention anything technical, I knew there'd be at least another post here...
If the field is a string containing a date, then the FORMAT of that date string is important to emulate when doing comparisons.
Try:
totext(CDate(DateAdd("m", -5, CDate({?@PostingDate}))),"yyyy-MM-dd")
As a kindness to everyone involved, please post technical information rather than text descriptions:
Crystal version
Database/connectivity used
Example data (show tables/fields/types)
Expecteed output (based on example data)
And why use a string field for the parameter? Date parms are easier to enter, and you can convert it to a string for comparison.
Better still, you might use a SQL Expression to convert the string date field in the table to a date on the database side to simplify things, but that would require knowing the database type and Crystal version.
You're too secretive
-k