Sometimes we need to join multiple tables to get aggregate data in return. here is how we can achieve the same using CodeIgniter Query Builder / Active Records.
public function getStudentInfo($studentid){
$query = $this->db->select("st.id, st.name, st.class, mk.maths, mk.science")
->from("students as st")
->join("marks as mk", "mk.student_id = st.id", "inner")
->where("st.id", $studentId)
->get();
return $query->result();
}
Here we use join() to join multiple tables and we can change join type in 3rd parameter like "inner", "left", "right" etc.