按DISTINCT计数表

Question

所以我的桌子上有这样的记录

表

ID    Department

1     Finance
2     Engineering
3     IT
4     Finance
5     IT
6     IT

我应该能够得到：

Count Department
3     IT
2     Finance
1     Engineering

有什么想法吗？

谢谢

Answer 1

使用WHERE限制行。

SELECT id, 1 AS valid, Department
FROM RECORDS
WHERE DATEDIFF(quitDate, hiredDate) < 730 AND Department = 'IT'