Query MySQL database find missing email addresses

January 26, 2022

I am trying to extract email addresses from given list, that not persists in MySql database. My query:

SELECT * 
FROM users 
WHERE `user_email` IN ('myemail@email.com', 'my2email@email.com', 'my3email@email.com')

First two email addresses are in database, but the last one is not. My target is to print only emails that are NOT in database. How is that possible?

>Solution :

SELECT * 
FROM (SELECT 'myemail@email.com' user_email
      UNION ALL
      SELECT 'my2email@email.com'
      UNION ALL
      SELECT 'my3email@email.com') emails_to_check_for
LEFT JOIN users USING (user_email)
WHERE users.user_email IS NULL;