$data['customerdata'] = $this->jobdone_model->getcustomer();

public function getcustomer() { 
//เลือก Column ถ้าเลือกทั้งหมดให้ใส่ '*'
$this->db->select('userid,company'); 
//เลือก Database
$this->db->from('tblclients'); $query = $this->db->get();
 return$query;
}

<select name="clientid" data-live-search="true" data-width="100%" class='form-control col-sm-3'>
 <?php foreach($customerdata->result() as $customer){ ?>
  <optionvalue="<?php echo$customer->userid?>"><?php echo$customer->company?></option>
 <?php } ?>
</select>