Rewrite MySQL query using Codeigniter Active record

Question

I have started CodeIgniter not long ago. Can some tell me how to rewrite this query

SELECT question.timestamp AS question_time, reply.timestamp AS reply_time, 
(SELECT DATEDIFF(reply_time, question_time)) AS time_used_to_reply 
FROM question JOIN reply ON question.id = reply.question_id WHERE question.company_id=someid

using the activerecord

Also any tutorial to quickly understand activerecord would be very appreciated. Thanks

Answer 1

After many researches, I ended up writing my own active record script.

$this->db->select(array('DATEDIFF(reply.timestamp, question.timestamp)'))
    ->from('question')
    ->join('reply', 'question.id = reply.question_id')
    ->where('question.company_id', $company_id);

Thanks