与内部连接的SQL计数

Question

我有一个缺席者的表，并且该表存储那些缺席者的studentids。

从这个表格中我必须找到总的参加者和总缺席者，为此我刚加入了包含特定部分的最大容量的部分表格。

因为我这个查询是

select COUNT(Attendance.studentid) as Absentees 
     ,Sections.Max-count(studentid) as Presentees 
from Attendance 
inner join Students 
on students.StudentId=Attendance.StudentId 
inner join Sections 
on Sections.CourseId=students.CourseId 
group by Sections.Max 

它的做工精细，同样的道理我怎么能找到性别明智presentees /缺席......性别列是学生表，任何人都可以给我一些想法，在此先感谢

Answer 1

只是性别栏添加到您的select ...列和group by，你会一行结束了对每个性别：

select COUNT(Attendance.studentid) as Absentees, 
     Sections.Max-count(studentid) as Presentees, 
     Students.Gender as Gender 
from Attendance 
inner join Students 
on Students.StudentId=Attendance.StudentId 
inner join Sections 
on Sections.CourseId=Students.CourseId 
group by Sections.Max, Students.Gender