Question

两个表格 - posts和users
列posts.user与users.id匹配我想以这种方式统计所有用户的所有帖子：

user1 5
user2 3
user3 9

...等等意味着来自user1的{{1}}有来自users的5个实例......等等。

posts

结果

$items = '';
$sql = "select users.name, posts.user from users inner join posts on users.id = posts.user";
$stmt = $db->query($sql);
while($row = $stmt->fetch()){
   $count = $stmt->rowCount();
   $items .= "<div><span class='spanuser'>" . $row['name'] . "</span> <span class='spancount'>" . $count . "</span></div>";
    }
    echo $items;

任何帮助？

Answer 1

您需要将GROUP BY与LEFT JOIN一起使用，例如：

SELECT u.name, COUNT(p.id) AS `count`
FROM users u LEFT JOIN posts p ON u.id = p.user
GROUP BY u.name;

这将为您提供所需的输出。

<强>更新

根据我们的讨论，为了获得今天的计数，您可以使用以下查询：

SELECT u.name, COUNT(p.id) AS `count`
FROM users u LEFT JOIN posts p ON u.id = p.user
WHERE DATE(datetime) = DATE(NOW())
GROUP BY u.name;

同样，您可以使用BETWEEN运算符来获取日期范围的相同计数，例如，过去7天，您可以使用此代码：

SELECT u.name, COUNT(p.id) AS `count`
FROM users u LEFT JOIN posts p ON u.id = p.user
WHERE DATE(datetime) BETWEEN DATE_ADD(NOW(), INTERVAL -7 DAY) AND DATE(NOW())
GROUP BY u.name;

此外，您需要更新php以使用查询返回的count，而不是rowCount，例如：

$items .= "<div><span class='spanuser'>" . $row['name'] . "</span> <span class='spancount'>" . $row['count'] . "</span></div>";

Answer 2

尝试使用Count()

这样做

$items = '';
$sql = "SELECT u.name,COUNT(p.user) as pCount FROM users u INNER JOIN posts p on u.id = p.user GROUP BY u.name";
$stmt = $db->query($sql);
while($row = $stmt->fetch()){
        $items .= "<div><span class='spanuser'>" . $row['name'] . "</span> <span class='spancount'>" . $row['pCount'] . "</span></div>";
}
echo $items;

Answer 3

您希望按用户分组并计算帖子数量，以获得您想要的最终总行数WITH ROLLUP，例如

SELECT COALESCE(User,'TOTAL') AS Name, 
       Count(Post.ID) AS CountOfPosts
FROM Users
LEFT JOIN Posts ON Posts.USer= Users.id
GROUP BY Users.id WITH ROLLUP

＆＃34;总计＆＃34; row实际上具有null值，因此我们使用COALESCE将null更改为TOTAL

Answer 4

尝试使用COUNT（）。要计算posts.user

https://www.w3schools.com/sql/sql_count_avg_sum.asp

统计表格中的所有帖子＆＃34;帖子＆＃34;关于来自表格＆＃34;用户＆＃34;

4 个答案: