Tag Archives: regular expression

How to validate e-mail address in MySQL

Most people validate e-mail addresses in a normal programming language, such as PHP and that is a very good idea when you process user input and such, however sometimes you want to validate data already entered in a database.

Take this example: you have a comments table where each person can enter an e-mail address, but since it’s an optional field you don’t even validate the input. However when you need to send a newsletter you don’t want to process all fields and validate one by one, you want to use a single query and just get all e-mail addresses (eventually by adding additional rules as well), so here’s how you can do it in MySQL:

FROM `m_comment`
WHERE `comment_url`
REGEXP ‘(.*)@(.*)\.(.*)’

Sure, you can optimize the query, but it’s a simple regular expression which .. well, in most cases is good enough.