Question

您能否为我提供以下方案的解决方案。

我有两张表employee_name和Employee_details。

让我们想一想，Employee_details表包含多年的数据。我想从两个表中检索数据。

表1：employee_name

emp_no  name    
1       A
2       B
3       C etc..

表2：Employee_details

emp_no col1 col2 address salary year  addr_changed_By addr_changed_on  sal_changed_by Sal_changed_on

1      x1   y1   addr1   100000 2013    P            01/12/2014      q              09/12/2014

1      x1   y1   addr2   150000 2014    P            01/12/2014      q              09/12/2014


2      x2   y2   addr4   200000 2014    m            19/12/2014      n              10/12/2014

我希望获得员工详细信息以及姓名。如果前3列在具有相同数据的第二个表中，我们应该得到单个记录。
此外，我需要更新记录时的数据以及数据更新了每个员工记录？

最后，根据以上数据，我想得到两条记录，如：

employee name: A
address : addr1
last updated by: q
last updated on : 09/12/2014

employee name : B
address : addr4
last updated by: m
last updated on : 19/12/2014

Answer 1

我会留给你取名字这只是薪水

select last.* 
from 
(
    select temp_no, col1, col2, address, salary, year
         , addr_changed_By, addr_changed_on, sal_changed_by, Sal_changed_on 
         , row_number() over (partition by temp_no, col1, col2 order by Sal_changed_on desc) as rownum 
      from Employee_details
) as last 
where rownum = 1

Answer 2

使用CROSS APPLY

SELECT emp_no, col1, col2, Changed_On, Changed_By
FROM employee_details ed
    CROSS APPLY (SELECT TOP 1
                    CASE WHEN addr_changed_on > Sal_changed_on THEN addr_changed_on ELSE Sal_changed_on END Changed_On,
                    CASE WHEN addr_changed_on > Sal_changed_on THEN addr_changed_By ELSE sal_changed_by END Changed_By
                FROM employee_details ed2
                WHERE emp_no = ed.emp_no 
                    AND col1 = ed.col1
                    AND col2 = ed.col2
                ORDER BY Changed_On DESC) chn
GROUP BY emp_no, col1, col2, Changed_On, Changed_By

并发布BLAM的代码......

select last.* 
from 
(
    select emp_no, col1, col2, address, salary, year, Changed_By, Changed_On 
         , row_number() over (partition by emp_no, col1, col2 order by Changed_On desc) as rownum 
      from Employee_details
        CROSS APPLY (SELECT CASE WHEN addr_changed_on > Sal_changed_on THEN addr_changed_on ELSE Sal_changed_on END Changed_On,
                            CASE WHEN addr_changed_on > Sal_changed_on THEN addr_changed_By ELSE sal_changed_by END Changed_By) chn
) as last 
where rownum = 1

如果我们在前三列中有重复项，则从第二个表中获取单个记录

2 个答案: