How to check for uppercase letters in MySQL?

问题:

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: character class:

SELECT 'z' REGEXP '^[[:upper:]]+$';

This gives true, although the z is in lower case,... why?

回答1:

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.

回答2:

change to case sensitive collation, eg.

CHARACTER SET latin1 COLLATE latin1_general_cs

then try this query,

SELECT 'z' REGEXP '^[A-Z]+$'

• SQLFiddle Demo

回答3:

For me this works and is not using a regexp. It basically compares the field with itself uppercased by mysql itself.

-- will detect all names that are not in uppercase
SELECT 
    name, UPPER(name) 
FROM table 
WHERE 
    BINARY name <> BINARY UPPER(name)
;