mysql - Adventure Works 用于 SQL 查询

Question

我的任务是查找在 2 个部门工作过的员工姓名，我觉得我的格式不正确，因为它只显示 1 个结果，而本应返回 4 个结果，如果有人可以查看一下如果我有一些语法错误，请告诉我，我们将不胜感激。

SELECT P.FirstName,LastName, COUNT(D.DepartmentID) as Departments
FROM HumanResources.EmployeeDepartmentHistory D
INNER JOIN Person.Person P ON P.BusinessEntityID = D.DepartmentID 
GROUP BY P.FirstName,LastName
HAVING COUNT(DepartmentID)=2

Answer 1

ON P.BusinessEntityID = D.DepartmentID - 不会给出合理的结果尝试ON P.BusinessEntityID = D.BusinessEntityID