Sql查询-生成；地段；具有相同ID的每组N个项目的列表上的编号

我遇到了一种情况，我需要写一个查询，但我不知道什么是最好的路线

假设我有这样的数据：

+------------+-------------------+
| EmployeeID |  ProjectStartDate |
+------------+-------------------+
| 1          |  01/01/2017       |
| 1          |  02/02/2017       |
| 1          |  03/03/2017       |
| 1          |  04/04/2017       |
| 1          |  05/05/2017       |
| 1          |  06/06/2017       |
| 1          |  07/07/2017       |
| 2          |  01/01/2017       |
| 2          |  02/02/2017       |
| 2          |  03/03/2017       |
| 2          |  04/04/2017       |
+------------+-------------------+

+------------+-------------+------------------+
| LotNumber  | EmployeeId  | ProjectStartDate |
+------------+-------------+------------------+
| 1          | 1           | 01/01/2017       |
| 1          | 1           | 02/02/2017       |
| 1          | 1           | 03/03/2017       |
| 1          | 1           | 04/04/2017       |
| 1          | 1           | 05/05/2017       |
+------------+-------------+------------------+
| 2          | 1           | 06/06/2017       |
| 2          | 1           | 07/07/2017       |
+------------+-------------+------------------+
| 1          | 2           | 01/01/2017       |
| 1          | 2           | 02/02/2017       |
| 1          | 2           | 03/03/2017       |
| 1          | 2           | 04/04/2017       |
+------------+-------------+------------------+

我需要为每个员工生成项目“批次”，但是批次有一个与每组N个（这里假设为5个）项目相关联的批次号。因此，我需要一个查询，可以按EmployeeID分组，按ProjectStartDate排序，然后将每个员工的结果动态分组为5组，为每个组分配一个增量计数。所以最终的结果是这样的：

+------------+-------------------+
| EmployeeID |  ProjectStartDate |
+------------+-------------------+
| 1          |  01/01/2017       |
| 1          |  02/02/2017       |
| 1          |  03/03/2017       |
| 1          |  04/04/2017       |
| 1          |  05/05/2017       |
| 1          |  06/06/2017       |
| 1          |  07/07/2017       |
| 2          |  01/01/2017       |
| 2          |  02/02/2017       |
| 2          |  03/03/2017       |
| 2          |  04/04/2017       |
+------------+-------------------+

+------------+-------------+------------------+
| LotNumber  | EmployeeId  | ProjectStartDate |
+------------+-------------+------------------+
| 1          | 1           | 01/01/2017       |
| 1          | 1           | 02/02/2017       |
| 1          | 1           | 03/03/2017       |
| 1          | 1           | 04/04/2017       |
| 1          | 1           | 05/05/2017       |
+------------+-------------+------------------+
| 2          | 1           | 06/06/2017       |
| 2          | 1           | 07/07/2017       |
+------------+-------------+------------------+
| 1          | 2           | 01/01/2017       |
| 1          | 2           | 02/02/2017       |
| 1          | 2           | 03/03/2017       |
| 1          | 2           | 04/04/2017       |
+------------+-------------+------------------+

通常情况下，我只会为批次创建一个表，但批次号可以动态更改，因为它们与最早日期生成的第一批批次的日期不符。因此，添加或删除项目将改变之后的每个批号

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有没有人想到一种有效的方法来做到这一点？

行数和整数除法的组合应该可以：

WITH CTE AS
(
    SELECT  *,
            RN = ROW_NUMBER() OVER(PARTITION BY EmployeeID ORDER BT ProjectStartDate)
    FROM dbo.YourTable
)
SELECT  (RN -1 )/5 + 1 LotNumber,
        EmployeeID,
        ProjectStartDate
FROM CTE
;

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感谢您提供如此简单、优雅的解决方案！查询在不到一秒钟的时间内运行了100000条记录！