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Question

我有两张桌子

schoolname    StudentID     Class
A       1       1
A       2       2
B       3       1
B       4       2
C       5       1
C       6       2
C       7       3

和

StudentID   Attendance
1       present
2       Absent
3       Absent
4       present
5       present
6       absent
7       absent

我想要像

这样的结果

schoolname  class1      class2      class3      present     absent
A       1       1       0       1       1
B       1       1       0       1       1
c       1       1       1       1       2

class1,2,3，根据studentid

显示和缺席计数

示例代码：

 ; with cte as 
    ( 
        select schoolname as [School Name]
        , count(studentid) as total 
        , class 
        from Student_Master 
        group by SchoolName
        , class 
    ) 
select [School Name]
,isnull(1,0)1 
,isnull(2,0)2
,isnull(3,0)3 
from cte 
pivot (sum(total) for [class] in (1,2,3) ) as p

Answer 1

为了方便起见，我使用了表变量，但您可以在最终解决方案中轻松替换永久表名。

示例数据设置：

declare @student_master table 
    (
        schoolname char(1) not null
        , studentid int not null
        , class int not null
    )

insert into @student_master values ('A', 1, 1)
insert into @student_master values ('A', 2, 2)
insert into @student_master values ('B', 3, 1)
insert into @student_master values ('B', 4, 2)
insert into @student_master values ('C', 5, 1)
insert into @student_master values ('C', 6, 2)
insert into @student_master values ('C', 7, 3)

declare @student_attendance table
    (
        studentid int not null
        , attendance varchar(10) not null
    )

insert into @student_attendance values (1, 'present')
insert into @student_attendance values (2, 'Absent')
insert into @student_attendance values (3, 'Absent')
insert into @student_attendance values (4, 'present')
insert into @student_attendance values (5, 'present')
insert into @student_attendance values (6, 'absent')
insert into @student_attendance values (7, 'absent')

然后我使用以下查询来获得所需的输出。

<强>答案：

; with classes as 
    (
        select post.schoolname
        , isnull(post.class1, 0) as class1
        , isnull(post.class2, 0) as class2
        , isnull(post.class3, 0) as class3
        from (
            select sm.schoolname
            , 'class' + cast(sm.class as varchar(4)) as col_nm
            , count(*) as col_val
            from @student_master as sm
            group by sm.schoolname
            , sm.class
            ) as pre
        pivot (sum(pre.col_val) for pre.col_nm in ([class1], [class2], [class3])) as post
    )
    , attendance as
    (
        select sm.schoolname
        , sum(case when sa.attendance = 'present' then 1 else 0 end) as present
        , sum(case when sa.attendance = 'absent' then 1 else 0 end) as [absent]
        from @student_attendance as sa
        inner join @student_master as sm on sa.studentid = sm.studentid
        group by sm.schoolname
    )
select c.schoolname
, c.class1
, c.class2
, c.class3
, a.present
, a.[absent]
from classes as c
inner join attendance as a on c.schoolname = a.schoolname

<强>输出：

schoolname  class1  class2  class3  present absent
A             1       1        0       1      1
B             1       1        0       1      1
C             1       1        1       1      2

Answer 2

不要从@Tarheel那里得到任何信任，只是采取一些不同的方法。

declare @student_master table 
(
    schoolname char(1) not null
    , studentid int not null
    , class int not null
)

insert into @student_master values ('A', 1, 1)
insert into @student_master values ('A', 2, 2)
insert into @student_master values ('B', 3, 1)
insert into @student_master values ('B', 4, 2)
insert into @student_master values ('C', 5, 1)
insert into @student_master values ('C', 6, 2)
insert into @student_master values ('C', 7, 3)

declare @student_attendance table
(
    studentid int not null
    , attendance varchar(10) not null
)

insert into @student_attendance values (1, 'present')
insert into @student_attendance values (2, 'Absent')
insert into @student_attendance values (3, 'Absent')
insert into @student_attendance values (4, 'present')
insert into @student_attendance values (5, 'present')
insert into @student_attendance values (6, 'absent')
insert into @student_attendance values (7, 'absent')


SELECT  schoolname, 
    SUM(CASE WHEN class = 1 then 1 else 0 end) AS Class1,
    SUM(CASE WHEN class = 2 then 1 else 0 end) AS Class2,
    SUM(CASE WHEN class = 3 then 1 else 0 end) AS Class3,
    SUM(CASE WHEN sa.attendance = 'present' THEN 1 ELSE 0 END) AS Present,
    SUM(CASE WHEN sa.attendance = 'absent' THEN 1 ELSE 0 END) AS Absent
    FROM @student_attendance AS sa
        INNER JOIN @student_master AS sm ON sa.studentid = sm.studentid 
    GROUP BY schoolname

Output:
schoolname  Class1  Class2  Class3  Present Absent
    A         1      1       0        1       1
    B         1      1       0        1       1
    C         1      1       1        1       2