SQL查询合并来自不同表的报告

Question

我有支持票证数据库，它们分为两个表，如Incidents ， Tasks 。
Incidents有田assigned_group ， open_time ， close_time
Tasks具有字段assignment ， issue_date ， close_date （含义相同，但名称不同）

现在，我需要针对特定​​时间段编写以下结构的报告：

Group | Total opened incidents + tasks | Total closed incidents + tasks)

单个查询如下所示：

-- Q1: Total opened incidents
SELECT assigned_group, COUNT(*) FROM incidents WHERE open_time BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' GROUP BY assigned_group

-- Q2: Total closed incidents
SELECT assigned_group, COUNT(*) FROM incidents WHERE close_time BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' GROUP BY assigned_group

-- Q3: Total opened tasks
SELECT assignment, COUNT(*) FROM tasks WHERE issue_date BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' GROUP BY assignment

-- Q4: Total closed tasks
SELECT assignment, COUNT(*) FROM tasks WHERE close_date BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' GROUP BY assignment

结果表应为

Group | Q1+Q3 | Q2+Q4

请注意，在每个查询中，行（组）的数量可以不同，例如，在特定时间段内没有打开任何任务，但是关闭了一些任务，这仍应计算在内

谢谢！

Answer 1

我是否正确地认为要获得Q1和Q3的总未解决事件和任务的总和（假设assigned_group和assignment对联接有效）？ 如果是这样，则以下子选项将返回未解决事件的总数

SELECT Incidents.IncidentCount + Tasks.TaskCount AS TotalOpenIncidents ,
       COALESCE(Incidents.assigned_group, Tasks.assignment) AS Group
FROM (
    SELECT assigned_group, COUNT(*) AS IncidentCount 
    FROM incidents 
    WHERE open_time BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' 
    GROUP BY assigned_group ) AS Incidents INNER JOIN
    (
    SELECT assignment, COUNT(*) AS TaskCount
    FROM tasks 
    WHERE issue_date BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' 
    GROUP BY assignment) AS Tasks ON Incidents.assigned_group = Tasks.assignment

您需要对Q2和Q4进行相同的操作以获取关闭的数量

Answer 2

要将此类数据粘贴在一起，可以使用“完全外部联接”或UNION ALL 。 这是UNION ALL方法：

有多种方法可以将该查询重构得更简单。 如果您有兴趣，我可以进一步介绍您，或者您可以自己尝试。 例如，您只需要Z子表中的2个查询。

如果您的联接列不是唯一的，则UNION ALL方法将停止重复计数（尽管这对您来说不是问题）

SELECT assigned_group, SUM(Closed) As Closed, SUM(Opened) As Opened
FROM
(
SELECT assigned_group, COUNT(*) As Closed, 0 As Opened
FROM incidents 
WHERE open_time BETWEEN '2014-01-01     00:00:00' AND '2014-02-01 00:00:00' 
GROUP BY assigned_group

UNION ALL

SELECT assigned_group, 0 As Closed, COUNT(*) As Opened
FROM incidents 
WHERE close_time BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' 
GROUP BY assigned_group

UNION ALL

SELECT assignment, 0 As Closed, COUNT(*) As Opened
FROM tasks 
WHERE issue_date BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' 
GROUP BY assignment

UNION ALL

SELECT assignment, COUNT(*) As Closed, 0 As Opened
FROM tasks 
WHERE close_date BETWEEN '2014-01-01 00:00:00' AND '2014-02-01 00:00:00' 
GROUP BY assignment
) Z
GROUP BY assigned_group,