将多个计数/组查询合并为一条语句

Question

我一直在研究一种为多个表中的用户返回计数的方法。

<?php

    $stmt = $db->prepare("SELECT `computer_username`, `computer_name`, COUNT(`computer_name`) `totalsum` FROM `table1`
        WHERE `account_id` = ? AND (`computer_name` = 'comp1' OR `computer_name` = 'comp2' OR `computer_name` = 'comp3')
        GROUP BY `computer_username`, `computer_name`
    ");

    $stmt->execute(array($_SESSION['user']['account_id']));
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);   
    //print out the array
    echo 'table1<br /><pre>',print_r($results,true),'</pre><br /><br />';

    $stmt = $db->prepare("SELECT `computer_username`, `computer_name`, COUNT(`computer_name`) `totalsum` FROM `table2`
        WHERE `account_id` = ? AND (`computer_name` = 'comp1' OR `computer_name` = 'comp2' OR `computer_name` = 'comp3')
        GROUP BY `computer_username`, `computer_name`
    ");

    $stmt->execute(array($_SESSION['user']['account_id']));
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);   
    //print out the array
    echo 'table2<br /><pre>',print_r($results,true),'</pre><br /><br />';

    $stmt = $db->prepare("SELECT `computer_username`, `computer_name`, COUNT(`computer_name`) `totalsum` FROM `table3`
        WHERE `account_id` = ? AND (`computer_name` = 'comp1' OR `computer_name` = 'comp2' OR `computer_name` = 'comp3')
        GROUP BY `computer_username`, `computer_name`
    ");

    $stmt->execute(array($_SESSION['user']['account_id']));
    $results = $stmt->fetchAll(PDO::FETCH_ASSOC);   
    //print out the array
    echo 'table3<br /><pre>',print_r($results,true),'</pre><br /><br />';

?>

对于每个数组，结果类似于以下内容：

Array
(
    [0] => Array
        (
            [computer_username] => Bob
            [computer_name] => comp1
            [totalsum] => 1
        )

    [1] => Array
        (
            [computer_username] => Steve
            [computer_name] => comp1
            [totalsum] => 27
        )

    [2] => Array
        (
            [computer_username] => Sue
            [computer_name] => comp2
            [totalsum] => 7
        )

)

我只是想返回数据库中每个表的每个组的总行数。 由于条件完全相同且仅表名不同，是否有一种方法可以在一次调用中返回全部内容？ 我整天都在玩它，但是到目前为止，对每个查询使用查询是我获得结果的唯一方法。

理想情况下，我正在寻找一个类似以下内容的数组结果：

Array
(
    [0] => Array
        (
            [computer_username] => Bob
            [computer_name] => comp1
            [table1] => 15
            [table2] => 34
            [table3] => 131
        )

        ... and so on for each computer_name/computer_username group

)

编辑：

我在这方面取得了一些进展...

SELECT * FROM

(SELECT computer_name, username, COUNT(computer_name) usercount
FROM users
WHERE `account_id` = ?
GROUP BY `username`, `computer_name`) a

JOIN 

(SELECT computer_name, computer_username, COUNT(computer_name) t1count
FROM t1
WHERE `account_id` = ?
GROUP BY `computer_username`, `computer_name`) b

JOIN

(SELECT computer_name, computer_username, COUNT(computer_name) t2count
FROM t2
WHERE `account_id` = ?
GROUP BY `computer_username`, `computer_name`) c

JOIN

(SELECT computer_name, computer_username, COUNT(computer_name) t3count
FROM t3
WHERE `account_id` = ?
GROUP BY `computer_username`, `computer_name`) d

ON a.username = b.computer_username AND a.username = c.computer_username AND a.username = d.computer_username

我从users表开始，因为它将始终列出所有用户名/计算机组的组合。 问题在于，要在数组中返回的任何结果，用户名/计算机组也必须在每个其他表中都包含条目（t1，t2，t3）。

可以这么说，在computer1上的Bob在t1中有5行，在t2中有10行，在t3中有50行，我将把这些计数以t1count，t2count，t3count的形式返回到我的数组中。 在computer4上的Sue在t1、0和t2中具有5，在t3中具有12 ...因为t2中没有行，所以不会返回她的任何结果。

有什么办法解决这个问题，或者联接是否明确要求从一个表到另一个表的匹配值？

示例数据和预期结果：

假设上面的所有表都有一个名为account_id = 1的列。您有一个account_id，它代表计算机的“所有者”。 用户是所有计算机以及这些计算机上所有用户名的表。 table1，table2，table3是与特定计算机和该计算机的特定用户相关联的记录。 在那些表中的任何特定用户/计算机对都可以有零个记录或任何数量的记录。

目标是在给定一个account_id和computer_name列表的情况下，为每个用户返回记录表（table1，table2，table3）的计数。 无需对结果进行任何排序。

Answer 1

使用提供的数据并且不提供要查询的ID即可完成您想要的操作。 看到工作FIDDLE

SELECT 
  usr, 
  cmptr, 
  t1_count, 
  t2_count, 
  t3_count 
FROM (
  SELECT
    users.username AS usr,
    users.computer_name AS cmptr,
    count(t1.computer_name) AS t1_count
  FROM users
  JOIN t1 ON t1.computer_username = users.username AND t1.computer_name = users.computer_name
  GROUP BY users.username, users.computer_name
)AS t
LEFT JOIN(
  SELECT
    users.username,
    users.computer_name,
    count(t2.computer_name) AS t2_count
  FROM users
  JOIN t2 ON t2.computer_username = users.username AND t2.computer_name = users.computer_name
  GROUP BY users.username, users.computer_name
) AS te ON te.username = t.usr OR te.computer_name = t.cmptr
LEFT JOIN(
  SELECT
    users.username,
    users.computer_name,
    count(t3.computer_name) AS t3_count
  FROM users
  JOIN t3 ON t3.computer_username = users.username AND t3.computer_name = users.computer_name
  GROUP BY users.username, users.computer_name
) AS tem ON tem.username = t.usr OR tem.computer_name = t.cmptr
GROUP BY usr, cmptr

将多个计数/组查询合并为一条语句

问题描述

1 个解决方案

解决方案1
1 已采纳 2014-05-06 01:09:37

将多个计数/组查询合并为一条语句

问题描述

1 个解决方案

解决方案1 1 已采纳 2014-05-06 01:09:37

解决方案1
1 已采纳 2014-05-06 01:09:37