$this->db->select('*');
$this->db->from('table1');
$this->db->join('table2', 'table1.id = table2.id');
$this->db->join('table3', 'table1.id = table3.id');
$query = $this->db->get();
$this->db->like('title', 'match'); $this->db->or_like('body', $match);
// WHERE `title` LIKE '%match%' ESCAPE '!' OR `body` LIKE '%match%' ESCAPE '!'
$table = "my_table";
$id = 1;
$update = ["status"=>"working"];
//Edit just above /\ if you don't need extra "where" clause
$query = $this->db->select()
->from($table)
->where('id', $id)
->get_compiled_select();
$data = $this->db->query("$query FOR UPDATE")->row_array();
$this->db->where('id', $data['id'])->update($table,$update);