Question

我有下表指定员工分配。 Null表示当前分配：

|EmployeeNum|EmployeeAssignment|BeginDate |EndDate   |
|1003       |Analyst           |01/01/1990|02/04/2013|
|1002       |Coordinator       |05/14/2000|06/01/2013|
|1003       |Trainer           |07/28/2010|NULL      |
|1004       |Janitor           |08/09/2013|NULL      |
|1005       |IT                |09/02/2013|12/21/2013|

另一张表格指定时间段和付费时间：

|EmployeeNum| DatePaid  |hworked|
|1003       | 05/11/2013|7.5    |
|1004       | 09/01/2013|8.25   |
|1005       | 09/15/2013|5.45   |

是否有一种方法可以使用SQL来比较两个表，以确定每个员工在工作时的分配？

Answer 1

简单INNER JOIN

SELECT * FROM table1 t1
INNER JOIN table2 t2 ON t1.employeenum = t2.employeenum

只需在查询中选择您想要的任何内容

Answer 2

我倾向于使用相关的子查询：

select t2.*,
       (select EmployeeAssignment
        from table1 t1
        where t1.employeenum = t2.employeenum and
              t2.datepaid between t1.begin_date and coalesce(t1.end_date, getdate())
       ) as EmployeeAssignment
from table2 t2;

编辑：

您也可以使用outer apply做同样的事情。实际上，根据您的数据结构，外部联接也应该起作用：

select t1.*, t2.EmployeeAssignment
from table1 t1 left join
     table2 t2
     on t1.employeenum = t2.employeenum and
        t2.datepaid between t1.begin_date and coalesce(t1.end_date, getdate())

TSQL匹配员工分配到时间戳

2 个答案: