匹配一个表的条目与另一个表中的两个日期之间的数据点

Question

我有两个表。他们目前在Access 2010中，但最终会迁移到Microsoft SQL 2010 DBMS。一个叫做EmployeeWages，另一个叫TimeClock。 EmployeeWages包含员工ID，工资和生效日期。 TimeClock表具有员工ID，与员工相关的工资以及工资有效的日期。

我需要做的是匹配雇员工作的正确工资。目前该表具有TimeIn和TimeOut字段。为了简单起见，在这个问题中，我已经计算了工作时间，但是如果我可以在一个查询中获得所有内容，那将非常棒。

EmployeeWage 
---------------------------------------------------------------------- 
| EmployeeID | RecordNum | EffectiveDate | WorkType | Wage | 
-+------------+-+-----------+-+---------------+-+----------+-+------+- 
| 6240  |  1  |  1/18/13  | Line | 6 | 
---------------------------------------------------------------------- 
| 6240  |  2  |  4/1/13  | Bench | 7 | 
---------------------------------------------------------------------- 
| 6240  |  3  |  6/1/13  | Min  | 7.35 | 
---------------------------------------------------------------------- 
| 6240  |  4  |  6/23/13  | Bench | 5 | 
---------------------------------------------------------------------- 
| 6240  |  5  |  6/24/13  | Bench | 6.25 | 
---------------------------------------------------------------------- 
| 6240  |  5  |  6/25/13  | Bench | 7.25 | 
---------------------------------------------------------------------- 

然后

TimeClock 
-------------------------------------------------- 
| EmployeeID | WorkType | Work Date| Hours | 
-+------------+-+----------+-+---------+-+------+- 
| 6240  | Line | 6/22/13 | 5 | 
-------------------------------------------------- 
| 6240  | Bench | 6/22/13 | 7 | 
-------------------------------------------------- 
| 6240  | Bench | 6/23/13 | 5 | 
-------------------------------------------------- 
| 6240  | Bench | 6/24/13 | 6.25 | 
-------------------------------------------------- 
| 6240  | Min  | 6/24/13 | 2 | 
-------------------------------------------------- 

产生的匹配表应该像...

TimeClock 
----------------------------------------------------------- 
| EmployeeID | WorkType | Work Date| Hours | Wage | 
-+------------+-+----------+-+---------+-+------+-+------+- 
| 6240  | Line | 6/22/13 | 5 | 6 | 
----------------------------------------------------------- 
| 6240  | Bench | 6/22/13 | 6.25 | 7 | 
----------------------------------------------------------- 
| 6240  | Bench | 6/23/13 | 6 | 5 | 
----------------------------------------------------------- 
| 6240  | Bench | 6/24/13 | 5.5 | 6.25 | 
----------------------------------------------------------- 
| 6240  | Min  | 6/24/13 | 2 | 7.35 | 
----------------------------------------------------------- 

任何帮助，使他们那里我将不胜感激！

Answer 1

SELECT T.EmployeeID, T.WorkType, T.[Work Date], T.Hours, 
(SELECT Max(E.EffectiveDate) 
FROM EmployeeWage E 
WHERE T.EmployeeID = E.EmployeeID 
AND T.WorkType = E.WorkType 
AND E.EffectiveDate <= T.[Work Date]) AS ActiveDate, 
E.Wage as Wage 
FROM TimeClock T, EmployeeWage EW 
WHERE T.EmployeeID = EW.EmployeeID 
AND TW.WorkType = EW.WorkType 
AND E.EffectiveDate = ActiveDate 

请注意，我没有MS-Access，也没有尝试过。如果有帮助或错误，请告诉我。

Answer 2

我不知道一个完美的方式与一个单一的查询，让您的结果，但是这会给你的基本信息，你需要：

SELECT TimeClock.EmployeeID, TimeClock.WorkType, TimeClock.WorkDate, EmployeeWage.EffectiveDate, TimeClock.Hours, EmployeeWage.Wage 
    FROM EmployeeWage INNER JOIN TimeClock 
    ON EmployeeWage.EmployeeID = TimeClock.EmployeeID 
    AND TimeClock.WorkType = EmployeeWage.WorkType 
    WHERE TimeClock.WorkDate >= EmployeeWage.EffectiveDate;