Question

我有一个员工的记录但是我的查询返回了这个员工的2条记录，因为地址栏的不同之处是2.如何才能解决这个问题？这是可以做到的吗？ EMP_ID，CUS_LAST_NAME，CUS_FIRST_NAME和GUARDIAN_ADDRESS来自3个单独的表格。

示例：

ID          EMP_ID      CUS_LAST_NAME   CUS_FIRST_NAME  GUARDIAN_ADDRESS
00000000    11111111    Jackson         Michael         1111 Street Apt 1

ID          EMP_ID      CUS_LAST_NAME   CUS_FIRST_NAME  GUARDIAN_ADDRESS
00000000    11111111    Jackson         Michael         1111 Street

Answer 1

使用max()快速而肮脏的方式：

select id, emp_id, emp_last_name, emp_first_name, max(address) as address
from employees
group by id, emp_id, emp_last_name, emp_first_name

替代方案：top with ties

select top 1 with ties
    id, emp_id, emp_last_name, emp_first_name, address
from employees
order by row_number() over (partition by emp_id order by address desc)

两者的rextester演示：http://rextester.com/EGGA75008

Answer 2

如果你不能删除其中一个如果你选择返回哪个地址无关紧要，你可以使用聚合函数只获得一行

select ID , EMP_ID , EMP_LAST_NAME,   EMP_FIRST_NAME,  min(ADDRESS)
from my_table 
group by ID , EMP_ID , EMP_LAST_NAME,   EMP_FIRST_NAME

Answer 3

如果要检测哪些员工有重复条目。

SELECT *
FROM employees
WHERE EMP_ID IN (
     SELECT EMP_ID
     FROM employees
     GROUP BY EMP_ID
     HAVING COUNT(*) > 1
   )

Answer 4

--start with unique list of clients
    SELECT DISTINCT a.ID, a.EMP_ID, e.EMP_LAST_NAME, e.EMP_FIRST_NAME,     e.ADDRESS
FROM TABLE1 a
--attach on employee data on id
    OUTER APPLY (SELECT TOP 1 b.EMP_LAST_NAME, b.EMP_FIRST_NAME, b.ADDRESS
    FROM TABLE2 b
    WHERE a.id = b.id 
--use order by clause to change order and choose what top employee record u     want to choose
    ORDER BY b.address 
    ) e

由于其中一列中的数据错误，因此查询返回的重复数据记录

4 个答案: