测试数据表
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学生表
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student(Sid,Sname,Sage,Ssex)
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Sid 学生编号,Sname 学生姓名,Sage 出生年月,Ssex 学生性别
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创建学生表表,添加对应的测试数据,测试数据如下
create table student(Sid varchar(10),Sname varchar(10),Sage datetime,Ssex varchar(10)); insert into student values('01' , '赵雷' , '1990-01-01' , '男'); insert into student values('02' , '钱电' , '1990-12-21' , '男'); insert into student values('03' , '孙风' , '1990-05-20' , '男'); insert into student values('04' , '李云' , '1990-08-06' , '男'); insert into student values('05' , '周梅' , '1991-12-01' , '女'); insert into student values('06' , '吴兰' , '1992-03-01' , '女'); insert into student values('07' , '郑竹' , '1989-07-01' , '女'); insert into student values('08' , '王菊' , '1990-01-20' , '女');
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课程表
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course(Cid,Cname,Tid)
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Cid 课程编号,Cname 课程名称,Tid 教师编号
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创建学课程表,添加对应的测试数据,测试数据如下
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create table course(Cid varchar(10),Cname varchar(10),Tid varchar(10)); insert into course values('01' , '语文' , '02'); insert into course values('02' , '数学' , '01'); insert into course values('03' , '英语' , '03');
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教师表
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teacher(Tid,Tname)
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Tid 教师编号,Tname 教师姓名
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创建学教师表,添加对应的测试数据,测试数据如下
create table teacher(Tid varchar(10),Tname varchar(10)); insert into teacher values('01' , '张三'); insert into teacher values('02' , '李四'); insert into teacher values('03' , '王五');
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成绩表
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sc(Sid,Cid,score)
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Sid 学生编号,Cid 课程编号,score 分数
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创建学成绩表,添加对应的测试数据,测试数据如下
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create table sc(Sid varchar(10),Cid varchar(10),score decimal(18,1)); insert into sc values('01' , '01' , 80); insert into sc values('01' , '02' , 90); insert into sc values('01' , '03' , 99); insert into sc values('02' , '01' , 70); insert into sc values('02' , '02' , 60); insert into sc values('02' , '03' , 80); insert into sc values('03' , '01' , 80); insert into sc values('03' , '02' , 80); insert into sc values('03' , '03' , 80); insert into sc values('04' , '01' , 50); insert into sc values('04' , '02' , 30); insert into sc values('04' , '03' , 20); insert into sc values('05' , '01' , 76); insert into sc values('05' , '02' , 87); insert into sc values('06' , '01' , 31); insert into sc values('06' , '03' , 34); insert into sc values('07' , '02' , 89); insert into sc values('07' , '03' , 98);
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要求:
一.查询" 01 "课程比" 02 "课程成绩高的学生的信息及课程分数
分析:
满足条件的 sc《成绩表》中，
1：获得同一个学生，
2：该学生的01课程比02课程高！！！
3：需要展示该学生的信息，及其01与02的分数
即：将满足以上三个条件的信息，在一张表中展示出来。
1、找出有01成绩的同学成绩信息
SELECT * from sc WHERE sc.CId='01'
-- 2、找出有02成绩的同学成绩信息
SELECT * from sc WHERE sc.CId='02'
-- 3、以上两种结果需要满足一定条件（1）SId要一致【同一人】（2）且01.score>02.score
SELECT* FROM (SELECT * from sc WHERE sc.CId='01')as a,(SELECT * from sc WHERE sc.CId='02')as b WHERE a.Sid=b.Sid and a.score>b.score;
-- 4.学生01_score和02_score成绩信息对比表
SELECT * from student RIGHT JOIN (SELECT a.SId,a.score 01_score,b.score 02_score FROM (SELECT * from sc WHERE sc.CId='01')as a,(SELECT * from sc WHERE sc.CId='02')as b WHERE a.SId=b.SId AND a.score>b.score) r ON student.SId=r.SId
--5.查询学生表信息，拼接 成绩信息表（对比信息的studentd.Sid = 对比信息表.Sid)
