获取加入两个或多个表的最大ID

Question

我有一个sql小提琴。 http://sqlfiddle.com/#!3/c92c75/4

我有两个下面显示的查询将显示输出。

SELECT (A.EMP_ID),A.EMP_NAME, A.EMP_NO, C.MAINT_CHANGE, 
      C.MAINT_ID FROM EMPLOYEE_MASTER A LEFT OUTER JOIN DESIGNATION_MAINTENANCE C ON A.EMP_ID = C.EMP_ID 
      AND C.MAINT_ID =(select top(1) MAINT_ID from DESIGNATION_MAINTENANCE order by MAINT_ID DESC) 


SELECT (A.EMP_ID),A.EMP_NAME, A.EMP_NO, C.MAINT_CHANGE, 
      C.MAINT_ID FROM EMPLOYEE_MASTER A LEFT OUTER JOIN DESIGNATION_MAINTENANCE C ON A.EMP_ID = C.EMP_ID 

实际输出中我需要的是

EMP_ID EMP_NAME EMP_NO MAINT_CHANGE MAINT_ID 
17 EMPLOYEE17 MNAME17 MNAME18 17 (null) (null) 
18 EMPLOYEE18 MNAME18 MNAME19 18 February, 28 2015 00:00:00 3 
19 EMPLOYEE19 MNAME19 MNAME20 19 (null) (null) 
20 EMPLOYEE20 MNAME20 MNAME21 20 (null) (null) 
21 EMPLOYEE21 MNAME21 MNAME22 21 December, 01 2014 00:00:00 5 

如何编写查询？任何帮助赞赏。

Answer 1

试试这个：

SELECT (A.EMP_ID),A.EMP_NAME, A.EMP_NO, C.MAINT_CHANGE, 
C.MAINT_ID FROM EMPLOYEE_MASTER A 
LEFT OUTER JOIN DESIGNATION_MAINTENANCE C 
    ON A.EMP_ID = C.EMP_ID 
where not exists(
    select 'next' 
    from employee_master a2 
    left outer join DESIGNATION_MAINTENANCE c2 
    ON A2.EMP_ID = C2.EMP_ID 
    where a2.emp_id = a.emp_id 
    and (c2.maint_id is null and c.maint_id is not null or 
    c2.maint_id > c.maint_id) 
) 

转到SQL Fiddle