Active Record is not displaying correct query - php

Question

Can anybody tell me why im not able to display the following query using active record in codeigniter. I suppose there is something wrong with TIMEDIFF in my select statement as theres no space between TOTAL and FROM
This is my active record query
$this->db->select('s.id, s.person_id, p.first_name, p.last_name, sch.id, sch.start_date, sch.start_hour, sch.end_hour, TIMEDIFF(sch.end_hour, sch.start_hour) AS total');
$this->db->join('staff s', 'sch.staff_id = s.id', 'left');
$this->db->join('persons p', 's.person_id = p.id', 'left');
$this->db->where('sch.start_date >=', $start);
$this->db->where('sch.start_date <=', $end);
$this->db->limit(10);
$query = $this->db->get('work_schedule sch');
And this is how is printed out
SELECT `s`.`id`,
`s`.`person_id`,
`p`.`first_name`,
`p`.`last_name`,
`sch`.`id`,
`sch`.`start_date`,
`sch`.`start_hour`,
`sch`.`end_hour`,
TIMEDIFF(sch.end_hour,`sch`.`start_hour)` AS totalFROM (`work_schedule` sch)
LEFT JOIN `staff` s ON `sch`.`staff_id` = `s`.`id`
LEFT JOIN `persons` p ON `s`.`person_id` = `p`.`id`
WHERE `sch`.`start_date` >= '2014-02-19'
AND `sch`.`start_date` <= '2014-02-20'LIMIT 10

Answer 1

You can try it.
$query = $this->db->select('s.id, s.person_id, p.first_name, p.last_name, sch.id, sch.start_date, sch.start_hour, sch.end_hour, TIMEDIFF(sch.end_hour, sch.start_hour) AS total', FALSE)
->from('work_schedule sch')
->join('staff s', 'sch.staff_id = s.id', 'left')
->join('persons p', 's.person_id = p.id', 'left')
->where('sch.start_date >=', $start)
->where('sch.start_date <=', $end)
->limit(10)
->get();
$result = $query->result();