Sql查询返回每个部门的员工数

Question

如果我有一个名为Employee的表：

，我是Sql查询的新手

Id, Name, Department
 1   tim  sales
 2   tom  sales
 3   jay  HR
 4   ben  design
 5   lin  design

我正在尝试编写一个返回每个部门员工数量的查询。

SELECT COUNT(Department) FROM Employee 

有没有人对如何改进此查询有任何建议？

****修改

如果我想返回同一部门的员工人数

，那该怎么办？

Answer 1

使用分组 SELECT COUNT(id), department FROM Employee GROUP BY department

OR

按WHERE条件 SELECT COUNT(id),Department FROM Employee WHERE Department='HR'

Answer 2

SELECT COUNT(id), department FROM Employee GROUP BY department;

Answer 3

SELECT COUNT([id]), [department] FROM [Employee], GROUP BY [department].