Question

我正在尝试使用不同的值更新多行，但是我只想使用一个UPDATE查询以获得快速结果。.下面是我尝试过的操作，但是执行时间很长，有时浏览器出现错误，我无法继续执行代码，有什么解决方案吗？

require_once'db.php';

$ price ='10000';

如果（$ _POST）{

    $sql_query = "SELECT * FROM views_by_user WHERE views > 0";
    $db = new database();
    $con = $db->dbconnect();
    $res = $db->query($con, $sql_query);

    if($res){

        $total_views = TotalViews();

        while($row = mysqli_fetch_assoc($res)){     

            $email = $row['email'];
            $user_views = $row['views'];            
                $old_balance = UserOldBalance($email);

            $percentage = ($user_views / $total_views) * 100;
            $percentage = number_format($percentage, 0);
            $earned_balance = ($price * $percentage) / 100;
            $new_balance = $old_balance + $earned_balance;

            $sql_query = "UPDATE users SET balance = '$new_balance' WHERE email = '$email'";
            $db = new database();
            $con = $db->dbconnect();
            $res = $db->query($con, $sql_query);

            if($res){

               $sql_query = "UPDATE views_by_user SET views = '0' WHERE email = '$email'";
               $db = new database();
               $con = $db->dbconnect();
               $res = $db->query($con, $sql_query);

               if($res){

                echo "Balance Updated Successfully For " . $email . "<br />";

                }
                else {
                    echo "Error Updating Views...";
                }

            }
            else {
                echo "Error Updating Balance...";
            }

        }

    }
    else {
        echo "error";
    }

}

}

function TotalViews（）{

$sql_query = "SELECT SUM(views) as 'total_views' FROM views_by_user";
$db = new database();
$con = $db->dbconnect();
$res2 = $db->query($con, $sql_query);

if($res2){

    while($row2 = mysqli_fetch_assoc($res2)){       
        $total_views = $row2['total_views'];
    }

}

return $total_views;

}

Function UserOldBalance（$ email）{

$sql_query = "SELECT gems_balance FROM users WHERE email = '$email'";
$db = new database();
$con = $db->dbconnect();
$res3 = $db->query($con, $sql_query);

if($res3){

    while($row3 = mysqli_fetch_assoc($res3)){
        $old_gems = $row3['gems_balance'];
    }

}

return $old_gems;

}

Answer 1

您当前的代码效率低下，我们可以尝试将其重写为单个MySQL更新查询。例如，您的第一个查询可能被重写为：

UPDATE users u
SET balance = gems_balance + 10000 * ROUND(views / (SELECT SUM(views) FROM views_by_user));
WHERE email = ?;

这样就无需像使用游标那样遍历表。相反，您可以执行一个语句。如果您只想更新给定的电子邮件，则将单个值绑定到上面的?。如果要更新整个表，则只需删除WHERE子句。

第二个查询（假设您希望将其应用于整个表）只是一个简单的全局更新：

UPDATE views_by_user
SET views = 0;

Answer 2

我找到了解决我问题的方法，我必须使用mysql查询，如下所示：

public class RegisterUserController {

  public void start(User user){

    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(ChatRoomAPI.BASE_URL)
            .addConverterFactory(GsonConverterFactory.create())
            .build();

    ChatRoomAPI chatRoomAPI = retrofit.create(ChatRoomAPI.class);

    Call<User> call = chatRoomAPI.registerUser(user);

    call.enqueue(new Callback<User>() {
        @Override
        public void onResponse(Call<User> call, Response<User> response) {

            Log.d("TAG" , "onResponse" + response.code());

        }

        @Override
        public void onFailure(Call<User> call, Throwable t) {

            Log.d("TAG" , "onFailure" + t.getCause());    //

        }
    });

  }

}

如何在一个更新查询上使用多个集合？

2 个答案: