php - How to write codeigniter code for mysql queries

one text

I have written some codeigniter code for below mentioned query. I need to find out if this is right or wrong.

Mysql code ??�

Select sum(profit) from budget_tbl where reg_date like ???2021-%??�;

Codeigniter - Model

function select_profit()
    {
      $this->db->select_sum("budget_tbl.profit");
       $this->db->from("budget_tbl");
       $this->db->like(???reg_date,'2021-','after');
        $qry=$this->db->get();
       return $qry -> result();    

    }