I want to check, if a string consits only of uppercase letters. I know that RLIKE/REGEXP are not case sensitive in MySQL. So I tried to use the :upper:
characte
REGEXP is not case sensitive, except when used with binary strings.
http://dev.mysql.com/doc/refman/5.7/en/regexp.html
So with that in mind, just do something like this:
SELECT * FROM `users` WHERE `email` REGEXP BINARY '[A-Z]';
Using the above example, you'd get a list of emails that contain one or more uppercase letters.