Duplicate Table Alias

Hi,

In some cases (multiple usermeta filtering done by other plugins), users filtering generates invalid SQL query, probably because code at https://plugins.trac.ww.wp.xz.cn/browser/new-user-approve/trunk/includes/user-list.php#L227 don’t use unique alias for $wpdb->usermeta (no alias or mt1).
Could you consider using unique alias for this queries ?

Thanks