Quick question with php

[Iskib]

Sinario:

I have a banned user table in my database

When a user signs up I want to check the username against this list.

in database banned usernames
test
admin
mod

I can do this with:

if (mysql_num_rows($ban_username_exists) != '0')

What is I wanted to check if any part of the username exsist in the database.

for example if the user tried to register
test1, test_now, testtaco
admin_me, admin1, adminme
mod1,mod_me,modme

What code would I use to pickup these partials ?