BINARY not recognized ??

Hi. My server has MySQL 3.23.58 installed, and I just migrated over from RedHat 7.2 to ES 3.0. Previously I was using the BINARY command to execute a case-sensitive search for member user names like this: SELECT * FROM mem WHERE BINARY user_name = 'SomeOne'; I now get an error from MySQL stating that "BINARYuser_name" is not a valid column. So, something seems to be broken. I looked through the MySQL online docs and BINARY is still there, but, it won't work for me. Anyone have the same problem or know why BINARY won't work anymore? There seems to be no other way to do simple case-sensitive string comparisons directly in MySQL. Thanks!