求一条sql
班级表(classes):班级id(id) ,班级名(class_name)
学生表(student):学生id(id),学生名(name),班级id(class_id)
要查:学生id,name,班级名,所在班级人数
mysql 怎么写啊
[解决办法]
select 学生id,name,c.class_name,(select count(*) from student where class_id=s.class_id) as 所在班级人数from student s ,classes cwhere s.class_id=c.id
[解决办法]
select s.id,s.name,c.class_name,count(*)from student s ,classes cwhere s.class_id=c.idgroup by s.id,s.name,c.class_name
[解决办法]
select 学生id,name,c.class_name,(select count(*) from student where class_id=A.class_id)
from student A INNER JOIN classes B ON A.class_id=B.id
[解决办法]
select a.id,a.name,b.class_name,(select count(*) from student where class_id=A.class_id)as'班级人数' from student aleft join classes bon a.id=b.class_id;