Question

我有一个名为Employee的sql表，其中包含EmployeeID，Status和DepartmentID列。现在我被分配了创建表格报告的任务，其中我需要一个部门的员工总数，活跃的员工数量（状态）和部门ID。使用Group By子句获取总员工数和相应的DepartmentID很简单。

Select count(*) as 'Total Employees',DepartmentID from Employees 
Group By DepartmentID

如何获得具有与外部查询相同的DepartmentID的特定状态的员工计数？如果您想要更多地澄清问题，请告诉我。

Answer 1

如果列Status的值有效，则无需外部查询

   Select count(*) as 'Total Employees',
          SUM(CASE WHEN status='Active' THEN 1 ELSE 0 END ) as TotalActiveEmployees,
          DepartmentID 
    from Employees 
    Group By DepartmentID

Answer 2

试试这个。

Select count(*) as 'Total Employees',
COUNT(CASE WHEN status='Active' THEN 1 ELSE 0 END ) as TotalActiveEmployees,
DepartmentID 
from Employees 
Group By DepartmentID

在子查询中的同一列上分组

2 个答案: