Question

Im trying to retrieve the values from MySQL database and convert it into int and than adding 3 to it and than trying to store the update int into database.Im not getting any error or anything.Initial value that i retrieve from database is 5 and than im trying to add 3 and than update the database.Now the updated value should be 8 but its not instead it just 3.I have no clue about what am i doing wrong so please help me out.

My php code from the index.php is following:

else if ($tag == 'addQuestion'){
                $username = mysql_real_escape_string($_POST['username']);
                $question = mysql_real_escape_string($_POST['question']);
                $tag1 = mysql_real_escape_string($_POST['tag1']);
                $tag2 = mysql_real_escape_string($_POST['tag2']);
                $tag3 = mysql_real_escape_string($_POST['tag3']);
                $time = $_POST['time'];
            $addQu = $db->addQuestion($username, $question, $tag1, $tag2, $tag3,$time);
        if($addQu){
            $q_id = $addQu["id"];
            $addQTA = $db->addQTA($username,$q_id,$question,$tag1,$tag2,$tag3);
            if($addQTA){
                $getKP= $db->getKP($username);
                if($getKP){

                                            //Having trouble at this part
                    $kp = (int)$getKP['karma_points'];
                    $ask_question_points = $kp + 3;

                    $updateKP= $db->updateKP($username,$ask_question_points);
                        if($updateKP){
                            $response["error"] =1;
                            $response["msg"] = "updateKP in AddQuestion Succesfull";
                            echo json_encode($response);
                    }
                    else{
                        $response["error"] =1;
                        $response["error_msg"] = "Error updateKP in AddQuestion";
                        echo json_encode($response);
                        }
                    }
                    else{
                        $response["error"] =1;
                        $response["error_msg"] = "Error inserting getKP in AddQuestion";
                        echo json_encode($response);
                        }
                }
            else{
                $response["error"] =1;
                $response["error_msg"] = "Error inserting QTA";
                echo json_encode($response);
                }
        }else{
            $response["error"] =1;
            $response["error_msg"] = "Error inserting question";
            echo json_encode($response);
            } 
            }

Here is the code of the function from DB_functions.php which handles update query:

public function updateKP($username,$karma_points){
        $result = mysql_query("UPDATE users SET karma_points = '$karma_points' WHERE username = '$username'") or die(mysql_error());
        return($result);
        }

Thank You!!

Answer 1

You should save yourself the headache and do it in one query:

$result = mysql_query("UPDATE users SET karma_points = karma_points + $karma_points WHERE username = '$username'") or die(mysql_error());

This will automatically increment your column karma_points for user $username with the value of $karma_points. Instead of doing the math in PHP and sending it back to MySQL, just do it in MySQL.