Microsoft SQL - 返回每个部门的男性、女性和总员工数量答案

【问题标题】：Microsoft SQL - Return amount of male, female and total staff for each respective departmentMicrosoft SQL - 返回每个部门的男性、女性和总员工数量
【发布时间】：2020-06-06 01:43:28
【问题描述】：

我正在努力解决这个问题。

基本上，我需要做的是创建一个查询，该查询返回一个表，该表对每个部门的所有女性、男性和员工总数进行计数。

到目前为止，我已经能够显示所有部门以及女性、男性和员工的总数，但不能显示每个单独的部门（它显示每个部门的数量相同）。

如何只显示每个部门的男性、女性和员工总数？？

问题和代码如下。以及代码产生的输出。

提前谢谢各位！

-- Username:
-- Q1004 For each of the different departments, show the number of current female, male and total
-- employees currently employed.
-- Schemas: HumanResources

-- Example output:
-- departmentName   female  male    totalEmployeeCount
-- Production        40     120         160

-- Write your query below


SELECT Name AS departmentName, 
(SELECT COUNT(gender) FROM AdventureWorksDB.HumanResources.Employee WHERE Gender = 'F') AS female,
(SELECT COUNT(gender) FROM AdventureWorksDB.HumanResources.Employee WHERE Gender = 'M') AS male,
(SELECT COUNT(gender) FROM AdventureWorksDB.HumanResources.Employee) AS totalEmployeeCount

FROM AdventureWorksDB.HumanResources.Department N 
JOIN AdventureWorksDB.HumanResources.EmployeeDepartmentHistory EDH 
ON N.DepartmentID = EDH.DepartmentID
JOIN AdventureWorksDB.HumanResources.Employee E
ON EDH.BusinessEntityID = E.BusinessEntityID
GROUP BY Name

输出看起来像这样

Department                female|male   |totalEmployeeCount
Engineering                84   |206    |290
Tool Design                84   |206    |290
Sales                      84   |206    |290
Marketing                  84   |206    |290
Purchasing                 84   |206    |290
Research and Development   84   |206    |290
Production                 84   |206    |290

【问题讨论】：

标签： mysql sql ddl dml

【解决方案1】：

使用条件聚合：

SELECT Name AS departmentName, 
       SUM(CASE WHEN e.gender = 'F' THEN 1 ELSE 0 END) as famale,
       SUM(CASE WHEN e.gender = 'M' THEN 1 ELSE 0 END) as male,
       COUNT(*) as totalEmployeeCount
FROM AdventureWorksDB.HumanResources.Department N JOIN 
     AdventureWorksDB.HumanResources.EmployeeDepartmentHistory EDH 
     ON N.DepartmentID = EDH.DepartmentID JOIN
     AdventureWorksDB.HumanResources.Employee E
     ON EDH.BusinessEntityID = E.BusinessEntityID
GROUP BY Name

【讨论】：