How to use something like meta_query but for fields?

get_users is a wrapper for WP_User_Query, which offers some additional parameters for searching specific columns.

$args = array(
    'search'         => $search,
    'search_columns' => array( 'user_login' )
);
$user_query = new WP_User_Query( $args );

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)