我有一个名为出勤的表,有2个属性(id,备注).我想从出勤表中显示缺席或迟到的每个身份证.
Attendance Table
|ID | Remarks |
=============================
|1 | Absent |
|1 | Late |
|2 | Absent |
|2 | Absent |
|3 | Late |
Sample Output
|ID | Absent | Late |
==================================
|1 | 1 | 1 |
|2 | 2 | |
|3 | | 1 |
目前,我只能使用以下代码输出2列(ID和Absent)或(ID和Late):
SELECT id, count(remarks) AS Absent
FROM attendance
WHERE remarks = 'Absent'
GROUP BY id;
我不能同时显示缺席和晚期列..请帮忙.谢谢.
最佳答案 这基本上是一个PIVOT.如果您无权访问PIVOT函数,则可以使用聚合函数和CASE语句复制它:
select id,
sum(case when remarks = 'Absent' then 1 else 0 end) Absent,
sum(case when remarks = 'Late' then 1 else 0 end) Late
from attendance
group by id
或者您可以使用COUNT():
select id,
count(case when remarks = 'Absent' then 1 else null end) Absent,
count(case when remarks = 'Late' then 1 else null end) Late
from attendance
group by id;