how to get mysql wpdb error in wordpress?[SOLVE]

Hello guys find here is the solutation for mysql error handling for wordpress. i marked red color

 $sql_order_query="INSERT INTO
                   customer_order_table_name  (  `id` , `cust_email`)
                   VALUES (NULL ,'BIKASH' )";

               if(false ===$wpdb->query($sql_order_query)){
                   $uf_error = $wpdb->print_error();
                   $this->debug_log("bikash mysql error : $uf_error",true);
                }