Sum of table rows will appear in a textfiled

Good day!

I have a problem in adding codes in my php codes, but i have the concept of codes that i want to add in my php codes, but I don’t know if it is right. Kindly check my codes thank you.

I attached my whole codes for better understanding

and here is the codes I want to add:

    $query = "SELECT * FROM clt_transact WHERE  clt_no = '" . $_POST . "'";
    $result_no = mysql_query($query);
            if(mysql_num_rows($result_no) > 0 )
            $operation2_input = 0;
            $query = "SELECT SUM(t.input_qty) AS operation_input FROM clt_traceability t, clt_transact p WHERE t.clt_transact_id = p.clt_transact_id AND t.operation_name 'Operation2' AND p.clt_no='" . $_POST["clt_no"] . "'";
            $resultyield = mysql_query($query);
                    if(mysql_num_rows($resultyield) > 0)$operation2_input =mysql_result($resultyield,0,"operation2_input");
              $operation2_total = $operation2_input;

I want to happen is all the input qty that the user insert in input qty textfield will sum and the result will appear in operation2_total in input_qty textfield.

I don’t know how thus the result should be appear automatically in the input qty of operation2_total and if my code is correct.

Thank you

I have 5 operation name: operation1,operation2,operation2_total,operation3,operation4,operation5. As you notice I have a operation2_total

How can I add the input qty of operation2 and the result will be appear in input_qty of operation2_total.