如何从3个JOINED表

Question

我正在尝试检查一个人姓名是否多次出现在表格中以及拉出附加信息（职位名称，部门名称，员工编号）以限制创建两个存储过程1.检查名称是否多次出现和2 。检查完成后获取附加信息。

我现在的查询现在如下，它返回多行，因为我用来加入表的ID在一个表中多次出现（一个员工可以属于多个部门，EmpID在这里多次出现，返回多个值）。

SELECT c.FirstName+ ' ' + c.LastName as emp_full_name, e.EmployeeNumber,
       e.EmpID, dh.PositionTitle, d.Name as deptName, e.isActive

FROM Person.Contact c

INNER JOIN HumanResources.Employee e ON c.ContactID = e.ContactID
INNER JOIN HumanResources.EmployeeDepartmentHistory dh ON e.EmpID = dh.EmpID
INNER JOIN HumanResources.Department d ON dh.DepartmentID = d.DepartmentID

WHERE c.FirstName+ ' ' + c.LastName LIKE @empName

我的一般表格结构如下：

Person.Contact

的ContactID

姓

名字

HumanResources.Employee

的EmpID

EmployeeNumber

isActive

HumanResources.EmployeeDepartmentHistory

DepartmentHistoryId

的EmpID

DepartmentID的

POSITIONTITLE

HumanResources.Department

DepartmentID的

名称

示例结果集：

John Doe 1234567  1 Database Architect Administration    A
John Doe 1234567  1 Database Tester    Administration    A

Answer 1

使用Distinct关键字

SELECT distinct c.FirstName+ ' ' + c.LastName as emp_full_name, e.EmployeeNumber,
       e.EmpID, STUFF((
      SELECT ',' + edh.PositionTitle
      FROM dbo.EmployeeDepartmentHistory edh
      WHERE edh.EmpID = e.EmpID
      FOR XML PATH(''), TYPE).value('.', 'NVARCHAR(MAX)'), 1, 1, ''), e.isActive

FROM Person.Contact c

INNER JOIN HumanResources.Employee e ON c.ContactID = e.ContactID
INNER JOIN HumanResources.EmployeeDepartmentHistory dh ON e.EmpID = dh.EmpID
INNER JOIN HumanResources.Department d ON dh.DepartmentID = d.DepartmentID

WHERE c.FirstName+ ' ' + c.LastName LIKE @empName
Group By e.EmpID