select sc.cid as 课程ID,course.name as 课程名 ,SUM(CASE WHEN scor

来源：学生作业帮编辑：灵鹊做题网作业帮分类：数学作业时间：2024/05/15 07:39:27

select sc.cid as 课程ID,course.name as 课程名 ,SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0
这是什么语法啊,
以下是全文
-- 23、统计列印各科成绩,各分数段人数:课程ID,课程名称,[100-85],[85-70],[70-60],[

首先,简单说一下case when语法：1、以CASE开头,以END结尾
2、分支中WHEN 后跟条件,THEN为显示结果
3、ELSE 为除此之外的默认情况,类似于高级语言程序中switch case的default,可以不加4、END 后跟别名

下面说一下你的语句：根据sc表中cid 和 course表中name 分组,然后对不同分数范围进行人数统计.
以SUM(CASE WHEN score BETWEEN 85 AND 100 THEN 1 ELSE 0 END) AS [100 - 85]为例,当score在85和100之间时,此条记录在总人数中增加1,否则为0（也就是不增加）,从而达到将这一分数段人数求和的目的.
其他的也是同样道理.

希望对你有帮助.

select sc.cid as 课程ID,course.name as 课程名 ,SUM(CASE WHEN scor select s.name,s.course,s.grade from student as s inner join SELECT CASE ABC.A WHEN'否' THEN'1' WHEN'是' THEN'-1' END AS 出入 sql函数,select count(A.abc) as sum from A left join B on A.id= select count(*) as total from 'test' order by id desc select Field_Content,ID*1 as ID,[index]=identity(int,1,1) in select * from student where name like '%[^ja,as,on]%' select id,name from student where id in ( select id from sco sql="select P.*,T.name as Typename from tb_function P inner 这个HQL语句是什么意思：select new list(p.name,p.add) from person as p $id="select id from account where name='".$_SESSION['login'] 把两个表的信息合并一个表是db_user 一个是db_score 表的内容分别是 ID, name和 ID ,scor