Here's more detail:

Select

Datediff(dd,MailRecd,MailReply)

As NumberDays

from tblMail

There are approx. 100,000 records in

tblMail. The dates in MailRecd and MailReply range from 12/01/2003 to 01/31/2004.

Example of records from tblmail:

MailRecd ...