Full Outer Join in Access 同时计算项目

Question

我正在尝试在 Access 中创建一个完整的外部联接，同时对项目进行计数并获取百分比。

这是我的代码：

SELECT Main.Draft, Count(Main.Draft) AS MainCount, (Count([Main.Draft])/(Select Count(Main.Draft) from Main)) AS Percentage
FROM Main LEFT JOIN Main_ChangeLog ON Main.ID = Main_ChangeLog.ID
GROUP BY Main.Draft;
UNION ALL 
SELECT Main.Draft, Count(Main.Draft) AS MainCount, (Count([Main.Draft])/(Select Count(Main.Draft) from Main)) AS Percentage
FROM Main RIGHT JOIN Main_ChangeLog ON Main.ID = Main_ChangeLog.ID
WHERE (((Main.Date) Between [Forms]![Main Reports]![txtbegin] And [Forms]![Main Reports]![txtend]))
GROUP BY Main.Draft;

这是我的结果：

Version_1   1   0
Version_2   1   0   
Version_3   3   0
Version_1   4   0
Version_2   3   0

这是我想要的结果：

Version_1   5   0.50
Version_2   4   0.15
Version_3   3   0.35

这是主要内容 table:

ID  CreateDate  FirstName   LastName   Draft

1   10/01/2020   First       One        Version_2
2   11/20/2020   Second      Person     Version_3
3   11/20/2020   Third       Girl       Version_3
4   11/21/2020   Fourth      Boy        Version_3
5   11/22/2020   Fifth       Guy        Version_1

这里是 Main_ChangeLog table:

ID CreateDate    FirstName   LasteName   Draft
1  9/10/2020      First       One       Version_1
2  9/10/2020      Second      Person    Version_1
2  10/10/2020     Second      Person    Version_2
3  9/10/2020      Third       Girl      Version_1
3  10/10/2020     Third       Girl      Version_2
4  9/5/2020       Fourth      Boy       Version_1
4  10/10/2020     Fourth      Boy       Version_2

每次在 Main table 上更新记录时，以前的记录都会存储在 Main_ChangeLog 中。它有助于真正了解每个月创建了多少个版本。

我刚刚将我的代码修改为：

  SELECT t.Draft, Count(t.Count) AS DraftCount, (Count(t.Draft)/(Select Count(t.Draft) from Main)) AS [Percentage]
    FROM 
    (SELECT Main.Draft as Draft, Main.Draft as [Count]
    FROM MainLEFT JOIN Main_ChangeLog ON Main.ID = Main_ChangeLog.ID 
    WHERE (((Main.Date) Between [Forms]![Main Reports]![txtbegin] And [Forms]![Main Reports]![txtend]))
    UNION ALL 
    SELECT Main.Draft AS Draft, Main.Draft as [Count]
    FROM MainRIGHT JOIN Main_ChangeLog ON Main.ID = Main_ChangeLog.ID
    WHERE (((Main.Date) Between [Forms]![Main Reports]![txtbegin] And [Forms]![Main Reports]![txtend])))  AS t
    GROUP BY t.Draft

现在我收到这个错误：

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression.

谢谢。

Answer 1

这是通过两个查询完成它的一种方法：

第一个查询（我们称之为 qryMainData）将使用 UNION ALL:

SELECT ID, Draft, CreateDate FROM Main
UNION ALL 
SELECT ID, Draft, CreateDate FROM Main_ChangeLog;

第二个查询将基于第一个，因为你想用查询1的整个结果集的总计数（qryMainData）来计算百分比：

SELECT Draft, Count(ID) as DraftQty, (SELECT COUNT(ID) FROM qryMainData) as TotalDraftQty,
ROUND(DraftQty/TotalDraftQty, 2) as DraftPercentage
FROM qryMainData
WHERE CreateDate Between [Forms]![Main Reports]![txtbegin] And [Forms]![Main Reports]![txtend]
GROUP BY Draft

MS Access 允许您在计算中使用字段别名。我还使用 ROUND 函数将结果四舍五入到小数点后两位。

Full Outer Join in Access 同时计算项目

Full Outer Join in Access while counting the items

sql

ms-access

ms-access-2013