SQL更新查询具体情况

Question

我使用Oracle 11g数据库，并有两个表：

EMP

ID EMPNO AGE DATE_PUBLISHED 

1 1001 11 14/01/1999 

2 1002 22 14/01/1999 

3 1003 33 14/01/1999 

4 1004 44 14/01/1999 

5 1005 55 14/01/1999 

6 1006 66 14/01/1999 

EMP_MIRROR

ID EMPNO AGE DATE_PUBLISHED 

1 1001 11 05/01/2004 

2 1123 54 05/01/2004 

3 1003 87 05/01/2004 

4 1004 65 05/01/2004 

5 1545 78 05/01/2004 

6 1006 14 05/01/2004 

我想更新DATE_PUBLISHED专栏基于以下条件210表：

如果在两个表的任何ID，存在的EMPNO或AGE的值的差，那么EMP_MIRROR的DATE_PUBLISHED柱应该被更新为SYSDATE。

EMP_MIRROR (after updation)

ID EMPNO AGE DATE_PUBLISHED 

1 1001 11 05/01/2004 

2 1123 54 07/07/2014 

3 1003 87 07/07/2014 

4 1004 65 07/07/2014 

5 1545 78 07/07/2014 

6 1006 14 07/07/2014 

结果集说明：

ID: 1 (EMPNO and AGE are same in both the tables, hence DATE_PUBLISHED is not updated) 

ID: 2 (EMPNO and AGE are different in both the tables, hence DATE_PUBLISHED is updated) 

ID: 3 (AGE is different in both the tables, hence DATE_PUBLISHED is updated) 

ID: 4 (AGE is different in both the tables, hence DATE_PUBLISHED is updated) 

ID: 5 (EMPNO and AGE are different in both the tables, hence DATE_PUBLISHED is updated) 

ID: 6 (AGE is different in both the tables, hence DATE_PUBLISHED is updated) 

请建议的查询可以达到这个效果。

Answer 1

这个标准的SQL解决方案（因为没有指定DBMS）将是：

UPDATE EMP_MIRROR 
SET  DATE_PUBLISHED = CURRENT_TIMESTAMP 
WHERE EXISTS 
     ( SELECT 1 
      FROM EMP 
      WHERE EMP.ID = EMP_MIRROR.ID 
      AND ( EMP.AGE <> EMP_MIRROR.AGE 
       OR EMP.EMPNO <> EMP_MIRROR.EMPNO 
       ) 
     ); 

Example on SQL Fiddle

Answer 2

UPDATE emp_mirror 
SET date_published = SYSDATE 
WHERE EXISTS (SELECT 1 
       FROM emp 
       WHERE emp.id = emp_mirror.id 
       AND ((emp.age != emp_mirror.age OR) 
        (emp.empno != emp_mirror.empno))); 

Answer 3

with temp as(
select [ID] 
     ,[DATE_PUBLISHED] 

from [EMP_MIRROR] 
inner join [EMP] on [EMP_MIRROR].[ID] = [EMP].[ID] 

where [EMP_MIRROR].[DATE_PUBLISHED] <> [EMP].[DATE_PUBLISHED] 
) 

update [EMP_MIRROR] set [DATE_PUBLISHED] = GETDATE() where ID = (Select [ID] from temp) 

有可能是一个更好的方式来做到这一点，但如果您要比较这两个表，然后选择日期不匹配到临时表中的ID，然后在该新的ID列表上使用更新。

只是供参考，我还没有检查过这个声明是否有效，但它的要点在那里，当我有时间测试时我会更新它。

Answer 4

可能

With CTE AS 
(
SELECT EM.* FROM EMP_MIRROR EM JOIN EMP E ON E.ID = EM.ID 
WHERE EM.AGE <> E.AGE OR E.EMPNO <> EM.EMPNO 
) 
Update EMP_MIRROR EE SET DATE_PUBLISHED = CURRENT_TIMESTAMP 
FROM CTE JOIN EMP_MIRROR ON CTE.EMPNO = EE.EMPNO