Question

我如何查看列（集合）的总和（userid = $ userid）？

示例：我需要查看用户id = 2，Collections = 200 + 330 = 530的结果，我需要查看此结果（ 530 ）

我的表

------------------------------
| id | user_id | Collections |
------------------------------
| 1  |    2    |     200     |
------------------------------
| 2  |    2    |     330     |
------------------------------
| 3  |    7    |     120     |
------------------------------
| 4  |    8    |     760     |
------------------------------
| 5  |    9    |     200     |
------------------------------
| 6  |    9    |     100     |
------------------------------

我的代码

<?php

$user_id = get_current_user_id();

$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "dbname";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$query = "SELECT SUM(Collections) FROM invoices where user_id = $user_id"; 

$result = mysql_query($query) or die(mysql_error());



// Print out result

?>

我是php＆amp;的初学者MySQL的

Answer 1

你可以试试这个：

SELECT SUM(i.Collections) AS totalCollection
FROM invoices AS i
WHERE i.user_id = '$user_id'
GROUP BY i.user_id

Answer 2

试试这个

SELECT SUM(Collections) AS totalvalue FROM invoices where user_id = '$user_id'

打印结果totalvalue

Answer 3

<强>第一

检查您的收集列类型。是String / Int / Date吗？它应该是数字（Int，double，float）

<强>第二

您的查询已经正确无误。但列名称应将其更改为结果

SELECT SUM(Collections) as result FROM invoices where user_id = $user_id

然后检查你的功能，从使用 mysqli 的连接，但在你的查询中你正在使用 mysql 这个应该被改为同一个功能。

<强>解决方案

<?php

$user_id = get_current_user_id();

$servername = "localhost";
$username = "root";
$password = "root";
$dbname = "dbname";

// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);

// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
} 

$query = "SELECT SUM(Collections) FROM invoices where user_id = $user_id"; 

$result = mysqli_query($link, $query) or die('query error');

print_r($result);
// Print out result

?>

Mysql - PHP - 查看总和列

3 个答案: