In databases I often see a table which as a "File As" Field which displays the last name "," & then the first name combine into one field. I wish to have this in my Employee Table.

I.E.
FirstName LastName FileAs
Mark Jones Jones, Mark

I'm assuming that the "FileAs" field is a calculated (text) field, but I can't figure out the expression in Expression Builder.

I tried:
[FirstName]"," and [LastName]
[FirstName]"," + [LastName]

Any suggestions would be apprechiated!