JOIN command for checking email address input by user against different email field in two tables
problem. I want users to be able to refer my a site but before sending the
email from the site, I want to check the email to see if 1) it has already
been registered as a user - user table or 2) it has already been referred
- referred table. When a user registers, their email goes into the registration
table. If they refer a user, that member's email(foreign key) and the user's
email goes into the referred table - if not already there.
Does anyone have an SQL command that they could suggest (or database setup)