Structure of a typical database table
PHP retrieves MySQL data to produce Web pages
The AID field associates each row in Jokes with a row in Authors
Never overload a table field to store multiple values, as is done here
The AID field associates each row of Emails with one row of Authors
The JokeLookup table associates pairs of rows from the Jokes and Categories tables
The structure of the finished jokes database
Standard joins take all possible combinations of rows