Question

我是Access的相对新手，其问题远远高于我的技能

我将有关Employees的信息存储在名为Current Employees的Access表中，该表包含名字，姓氏，员工ID等。

由于员工经常更换班次/职位，我需要一种方法来存储他们的职位，班次等历史记录，而无需为拥有大量冗余数据的员工存储两条记录。

所以我创建了第二个名为Assignment History的表，其中包含Employee ID之间的关系，其中可以有多个相同Employee ID的条目，看起来像

Employee ID | Assigned As Of | Job Title | Shift
1234        | 01/01/2017     | Manager   | A
1234        | 12/01/2016     | Salesman  | A 
5678        | 12/01/2016     | Salesman  | B

现在出于各种形式的原因，我想把最近的价值放回到我的第一个表当前员工的当前职位位置，如此

Employee ID | FName         | Last Name | Current Job
1234        | John          | Smith     | Manager
5678        | Steve         | Adams     | Salesman

我能够得到的最接近的是创建表查询到第三个表CurrAssign，其中代码是

SELECT a.* 
INTO CurrAssign
FROM AssignmentHistory AS a 
INNER JOIN (
     SELECT max(a.AssignedAsOf) AS LatestDate, a.EmployeeID 
     FROM AssignmentHistory AS a GROUP BY a.EmployeeID)  
AS SubMax 
ON (a.EmployeeID = SubMax.EmployeeID) 
AND (a.AssignedAsOf = SubMax.LatestDate);

有关如何将此查询更改为当前员工的更新的任何帮助？或者有更好的方法来格式化和存储这些信息吗？

Answer 1

你可以尝试一个简单的＆＃34;查找＆＃34;做法。这会有用吗？

SELECT ce.EmployeeID, ce.FName, ce.LName,
(SELECT TOP 1 ah.[Job Title] FROM AssignmentHistory ah WHERE ah.EmployeeID = ce.EmployeeID ORDER BY ah.AssignedAsOf DESC) AS CurrentJob--Look up Current Job
FROM CurrentEmployee ce

Answer 2

由于MS Access要求更新查询为updateable，因此请考虑在查询中使用嵌套域聚合DLookUp和DMax：

UPDATE Employees e    
SET e.[Current Job] = DLookUp("[Job Title]", "[Assignment History]", 
                              "[Employee ID]=" & e.[Employee ID] & 
                              " AND [Assigned As Of]=#" & 
                              DMax("[Assigned As Of]", "[Assignment History]", 
                                   "[Employee ID]=" & e.[Employee ID]) & "#")

使用第二个表中的最新值更新查询

2 个答案: