指望條件在同一列

搜索了很多之後，我要在這裏請教高手...指望條件在同一列

表1（考勤）

 
att_id att_date class_id student_id att_status 
    1  07-11-2013  1   1   P 
    2  07-11-2013  1   2   L 
    3  07-11-2013  1   3   P 
    4  07-11-2013  1   4   P 
    5  08-11-2013  2   5   P 
    6  08-11-2013  2   6   P 
    7  08-11-2013  2   7   A 
    8  08-11-2013  2   8   P 
    9  09-11-2013  1   1   L 
10  09-11-2013  1   2   P 
11  09-11-2013  1   3   A 
12  09-11-2013  1   4   P 
13  09-11-2013  2   5   P

凡att_status P =目前，A =缺席， L =離開。現在我想統計個別學生出席，缺席和離開，根據班級編號。

所需的結果

 
stu_id  class_id Present Absent Leave 
    1   1   1   0  1 
    2   1   1   0  1 
    3   1   1   1  0 
    4   1   2   0  0 
    5   2   1   0  0 
    6   2   1   0  0 
    7   2   0   1  0 
    8   2   1   0  0

來源

2013-11-10 user2782577

select student_id, 
     class_id, 
     sum(att_status='P') as present, 
     sum(att_status='A') as absent, 
     sum(att_status='L') as leave 
from attendance 
group by student_id, class_id

來源

2013-11-10 07:41:02

指望條件在同一列

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