Select 条出现不止一次的记录

Question

我正在尝试 select 出现不止一次并且属于特定部门和其他部门的记录。

到目前为止，我的查询是这样的：

SELECT employeeCode, employeeName
FROM
    Employees
WHERE
    Department <> 'Technology' 
    AND employeeCode IN (SELECT employeeCode 
            FROM Employees 
            GROUP BY employeeCode HAVING COUNT(*) > 1)

问题是我想 select 属于技术部门的员工，但他们也参与其他部门。

所以，他们肯定是科技部的，但也有可能是家居部的。在数据库中它可能看起来像：

1  |  A1  |  Alex  |  Technology
2  |  A2  |  Thor  |  Household
3  |  A3  |  John  |  Cars
4  |  A3  |  John  |  Technology
5  |  A4  |  Kim   |  Technology
6  |  A4  |  Kim   |  Video Games

所以基本上查询应该 return:

  A3  |  John  |  
  A4  |  Kim   |

我认为这是我遗漏的一小部分但是.. 关于如何 filter/sort 它始终使用该技术和其他部门的任何想法？

顺便说一句，我尝试搜索但找不到像我这样的问题..

Answer 1

试试这个：

SELECT E.employeeCode, E.employeeName
FROM Employees E
INNER JOIN (SELECT DISTINCT E1.employeeCode, E1.employeeName
            FROM Employees E 
            WHERE E.Department = 'Technology'
           ) AS A ON E.employeeCode = A.employeeCode AND E.employeeName = A.employeeName
GROUP BY E.employeeCode, E.employeeName 
HAVING COUNT(*) > 1;

Answer 2

如果您想要技术部门和其他部门的员工：

select e.employeeCode, e.employeeName
from employees e
group by e.employeeCode, e.employeeName
having sum(case when e.department = 'Technology' then 1 else 0 end) > 0 and
       count(*) > 1;

假设 table 中没有重复项。如果它可以有重复项，则使用 count(distinct department) > 1 而不是 count(*) > 1.

Answer 3

您可以在具有不同条件的相同 table 上将 EXISTS 与关联子查询结合使用。

SELECT e1.employeeCode, e1.employeeName
FROM Employees e1
WHERE e1.Department = 'Technology' 
AND EXISTS (SELECT * FROM Employees e2 
            WHERE e1.employeeCode = e2.employeeCode 
            AND e2.Department <> 'Technology')

Answer 4

这适用于您的情况：

SELECT a.employeeCode, a.employeeName
FROM Employees a, Employees b
WHERE 
     a.Department = 'Technology'
     AND
     b.Department <> 'Technology'
     AND 
     a.employeeCode = b.employeeCode
     AND 
     a.employeeID <> b.employeeID

Select 条出现不止一次的记录

Select records that appear more than once

sql

sql-server

sql-server-2008