UC知道一个很简单的SQL语句.求助
来源：百度知道 编辑：UC知道 时间：2024/05/27 14:26:35
表mark字段 值
name zhangsan,lisi,wangwu,zhaoliu,chenqi,dingba
mark 20,30,40,50,60,70
class 1,2,2,3,1,3
我现在想以班级(class)为条件分类查询出总的mark
一条语句是 select sum(mark) from userinfo where class=1;
我现在按team来查询不可能写三条吧?
select sum(mark) from userinfo where class=2,
select sum(mark) from userinfo where class=3
求高手把这3条记录整合为一条记录!
name zhangsan,lisi,wangwu,zhaoliu,chenqi,dingba
mark 20,30,40,50,60,70
class 1,2,2,3,1,3
我现在想以班级(class)为条件分类查询出总的mark
一条语句是 select sum(mark) from userinfo where class=1;
我现在按team来查询不可能写三条吧?
select sum(mark) from userinfo where class=2,
select sum(mark) from userinfo where class=3
求高手把这3条记录整合为一条记录!
select class , sum(mark)
from userinfo
group by class
select case when class =1 then sum(mark) else 0 end as '一班'
,case when class=2 then sum(mark) else o end as '二班'
,case when class=3 then sum(mark) else o end as '三班'
显示结果为:
|一班-|-二班-|-三班|
|1000-|-500--|-1500|
汇总查询数据的一条sql，用group就可以实现了。
select class,sum(mark) from userinfo group by class
select class,sum(mark) from [userinfo] group by class
SELECT CLASS,SUM(MARK)
FROM USERINFO
GROUP BY CLASS
结果：
CLASS SUM(MARK)
1 80
2 70
3 120
没有理解..
是指一条语句查询 class= 1,2,3 的 sum(mark) 吗?
select sum(mark) from userinfo where class in (1,2,3)