$this->addFields( [ 'user_name' ] );
$this->addFields( UserGroupMembership::selectFields() );
$this->addWhere( 'ug_expiry IS NULL OR ug_expiry >= ' .
$this->addFields( [ 'user_name' ] );
$this->addFields( UserGroupMembership::selectFields() );
$this->addWhere( 'ug_expiry IS NULL OR ug_expiry >= ' .