SUM CASE mysql

contoh :

SELECT *,SUM(CASE WHEN kode_pesanan = 'saYmWcq' THEN harga ELSE harga END)as total FROM `purchase_order` LEFT JOIN member on purchase_order.id_member=member.id_member where member.id_member !=0 and member.email='".$_SESSION['email']."' GROUP BY kode_pesanan