Update/add character to string

[Guest]

I have a text field that contains 7 characters. I need to put a hyphen
between characters 5 and 6, before the last two rightmost characters.

Field is xxxxxxx and should be xxxxx-xx. I know how to use replace in an
update query, but replace doesn't seem to fit. Can someone give me some
direction?

 

[LeAnne]

UPDATE MyTable
SET MyTextField = Left([MyTextField],5) & "-" & Right([MyTextField],2);