mysql - I want to sort the data based on concatenated columns -


i have code

$this->db->select("*")->from("events")->join("employees" , "events.event_manager_id = employees.employee_id")->where('events.status' , 1)->order_by(concat('events.event_start_date'.' '.'events.event_start_time','desc'));

event_start_date in format yyyy-mm-dd , event_start_time in hh:mm:ss

i want sort data based on concatenated event_start_date , event_start_time giving me error. ideas?

i've no idea why want use concat here. ?

$this->db     ->select("*")     ->from("events")     ->join("employees" , "events.event_manager_id = employees.employee_id")     ->where('events.status' , 1)     ->order_by("events.event_start_date",'desc');     ->order_by("events.event_start_time",'desc');

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