SQL Operator Problem!

[personnongrata]

Hello!

I got an query like that
SELECT *, fullname AS Expr1, email AS Expr2, is_active AS Expr3, login_name AS Expr4
FROM test.users
WHERE (fullname <> '<NULL>') AND (is_active = 1) AND (login_name <> 'a\0x5F\*')
ORDER BY fullname

But the Problem is that the expression " login_name <> 'a\0x5F\*' " does not return the results i wished! What I want is an exclue of "login_name"values starting with
'a_' but '_' in an SQLquery is handle like an space an \0x5F\ doesn' seems to work!

Can someone help me?

Thanx a lot!