SQL 根據列值對行進行分組

Question

地址表示例

ID, EmployeeID, Address

1, 100, TownA
2, 200, TownA
3, 300, TownB

我如何才能返回每個唯一地址的所有員工人數？

例如

EmployeeCount, Address

2 TownA
1, TownB

Answer 1

你應該按照這個思路做一些事情。

SELECT count(EmployeeID) as EmployeeCount, Address FROM table GROUP BY Address

Answer 2

這是一個簡單的分組

SELECT Count(*) EmployeeCount, Address
FROM yourTable
GROUP BY Address