no result on my screen in eloquent

i try to get first login and last login
->leftJoin('cfg_agent','cfg_agent.LOGIN_ID','=','datamart_agent_details.AGENT_ID')
->selectRaw('AGENT_ID') ->selectRaw('CONCAT(LAST_NAME," ",FIRST_NAME ) as AGENT_Name') ->selectRaw('EVENT_TIME as First_Login' ) ->where('EVENT','LOGIN') ->orderBy('EVENT_TIME', 'asc') ->selectRaw('EVENT_TIME as Last_Logout' ) ->where('EVENT','logout')

via Chebli Mohamed