一条sql统计一个班级的男女人数

有一个学生记录的表student，形式如下：   
  name   class   sex   
  1     a       男    
 2       b       女   
 3       c       男   
 4       a       男   
 5       a       女   
 6       a       男    
  ……    
  现要统计每个班级的男女人数，结果如下：   
  class  男  女    
 a       3   1   
 b       0  1    
 c       1  0    
  用一句select语句实现

 SQL:

create table student
(
  sID int identity(1,1) primary key notnull,
  sname varchar(8) not null,
  class int not null,
  sex char(2) not null
)
go

insert into student values('admin',1,'男')
insert into student values('111',1,'女')
insert into student values('张三',2,'男')
insert into student values('hui',2,'女')
insert into student values('李四',2,'男')
insert into student values('xin',3,'女')
insert into student values('xin',3,'女')
go

select * from student

select class , sum(case sex when '男' then 1else 0 end ) as '男' ,女=sum(case sex when '女' then 1 else 0end)
from student group by class

 

ORACLE:

create table student
(
  sID number primary key not null,
  sname varchar2(8) not null,
  class int not null,
  sex char(2) not null
)

 

insert into student values(seq_id.nextval,'admin',1,'男');
insert into student values(seq_id.nextval,'111',1,'女');
insert into student values(seq_id.nextval,'张三',2,'男');
insert into student values(seq_id.nextval,'hui',2,'女');
insert into student values(seq_id.nextval,'李四',2,'男');
insert into student values(seq_id.nextval,'xin',3,'女');
insert into student values(seq_id.nextval,'xin',3,'女');

select * from student;

select class,sum(decode(sex,'男',1,0))男,sum(decode(sex,'女',1,0))女  
from student  
group by class;

 

select class,sum(F),sum(M)from 
(  
select   class,count(*) F, 0 Mfrom student where sex='男'group  by  class  
union  
select   class,0 F ,count(*) Mfrom student where sex='女'group  by  class  
)  
group  by   class

 

扩展:一个班级只有一个男生很女生,在一条记录上分别显示姓名

insert into student values('admin',1,'男')
insert into student values('111',1,'女')
insert into student values('张三',2,'男')
insert into student values('hui',2,'女')

预期结果

class      男       女       
1          admin   111
2          张三     hui

SQL:

①:
select a.class,a.sname as '男',b.sname as'女'
from student a inner join student b on a.class=b.class
where a.sex='男' and b.sex='女'

②:

select a.class,a.sname as '男' ,b.sname as'女' from
(select * from student where sex='男')a,
(select * from student where sex='女')b
where a.class=b.class