1、select b.id,b.name,a.
from su_ a,
student b,
subject c
where a.sno = c.no
and a.sid = b.id
and b.name = '王雷'
and c.sna = '数学'
2、select b.id,b.name,average(a.)
from su_ a,
student b,
subject c
where a.sno = c.no
and a.sid = b.id
and b.name = '王雷'
group by b.id,b.name,a.sno
剩下的自己学着写,哪家的老师出这么没创意的题目?
要是有几十个叫王雷的怎么办?要是有几个科目有相同的名字怎么办?谁家的学校数据库里永远只有一个“高三一班”?
好好学习,天天向上,也要选点好题目嘛
from su_ a,
student b,
subject c
where a.sno = c.no
and a.sid = b.id
and b.name = '王雷'
and c.sna = '数学'
2、select b.id,b.name,average(a.)
from su_ a,
student b,
subject c
where a.sno = c.no
and a.sid = b.id
and b.name = '王雷'
group by b.id,b.name,a.sno
剩下的自己学着写,哪家的老师出这么没创意的题目?
要是有几十个叫王雷的怎么办?要是有几个科目有相同的名字怎么办?谁家的学校数据库里永远只有一个“高三一班”?
好好学习,天天向上,也要选点好题目嘛
select from su_ a where a.sid = (select id from student where name = "王雷")
and sno = ( select sno from subject where sna = "数学");
2 统计‘王雷’的平均分;
select avg() from su_ a where a.sid = (select id from student where name = "王雷");
3 统计‘高三一班’所有‘数学’和‘英语’均在95分以上的女生人数;
4 按照科目分类现实‘高三一班’该科的平均分
from su_ a join student b
on a.sid=b.id
join subject c
on a.sno=c.sno
where b.name='王雷' and c.sna='数学';--the second oneselect avg()
from su_ a
where exists(select 1 from student where id=a.sid and name='王雷');
from su_ a
where exists(select 1 from students
where id=a.sid and classid=(select id
from class
where cname='高三一班' ));
Where a.sno=c.sno And b.Id=c.sid And b.Name='王雷' And a.sna='数学';Select Avg(c.) From subject a,sudent b,su_ c
Where a.sno=c.sno And b.Id=c.sid And b.Name='王雷' ;Select Count(*) From subject a,sudent b,su_ c,Class d
Where a.sno=c.sno And b.Id=c.sid And b.classid=d.Id And d.cname='高三一班' And b.sex='f'
And (a.sna='数学' And c.>95 ) And (a.sna='英语' And c.>95 );Select a.sna,Avg(c.) From subject a,sudent b,su_ c,Class d
Where a.sno=c.sno And b.Id=c.sid And b.classid=d.Id And d.cname='高三一班'
Group By a.sna;