This stored procedure is a simple e-mail address validator — it makes sure the e-mail address is in the format firstname.lastname@example.org, and makes sure there are no special characters:
( ) <> @ , ; : \ . [ ] */
I allow ” because technically you can have “word”@word.com.
Folks can easily add to this snippet to make it fully compliant with RFC822 if they want. (I got bored and didn’t really feel like adding all that other stuff in. 🙂 )