in statement codeigniter 3 code example

Example 1: codeigniter raw query

$sql="Select * from my_table where 1";    
    $query = $this->db->query($SQL);
    return $query->result_array();

Example 2: where group codeigniter

$this->db->select('*')->from('my_table')
        ->group_start()
                ->where('a', 'a')
                ->or_group_start()
                        ->where('b', 'b')
                        ->where('c', 'c')
                ->group_end()
        ->group_end()
        ->where('d', 'd')
->get();

// Generates:
// SELECT * FROM (`my_table`) WHERE ( `a` = 'a' OR ( `b` = 'b' AND `c` = 'c' ) ) AND `d` = 'd'