Maynor的博客

表名和字段–1.学生表Student(s_id,s_name,s_birth,s_sex) --学生编号,学生姓名, 出生年月,学生性别–2.课程表Course(c_id,c_name,t_id) – --课程编号, 课程名称, 教师编号–3.教师表Teacher(t_id,t_name) --教师编号,教师姓名–4.成绩表Score(s_id,c_id,s_score) --学生编号,课程编号,分数–建表–学生表CREATE TABLE Student(s_id VARCHAR(2

show databases ;create database newTest;use newTest;CREATE TABLE STUDENTS(sno VARCHAR(3) NOT NULL,sname VARCHAR(4) NOT NULL,ssex VARCHAR(2) NOT NULL,sbirthday DATETIME,class VARCHAR(5));CREATE TABLE COURSES(cno VARCHAR(5) NOT NULL,cname VARCHAR

24、查询选修某课程的同学人数多于5人的教师姓名。答案:select tname from TEACHERS where tno in (select tno from COURSES where cno in ( select cno from SCORES sc group by cno having count(sc.sno)>5));

Mysql 的卸载之路 与Linux安装mysql的曲折1.Mysql 的卸载2.Linux安装mysql3.解决中文乱码

– 1、查询"01"课程比"02"课程成绩高的学生的信息及课程分数我的答案:select st.*,sc.s_score '语文',sc2.score2 '数学',inner join score sc on sc.s_id =st.s_id and sc.c_id='01'inner join score sc2 on sc2.s_id =st.s_id and sc2.c_id='02'where sc.s_score> sc2.s_score标准答案:SELECT s

– 22、查询所有课程的成绩第2名到第3名的学生信息及该课程成绩`SELECT t1.* FROM(SELECT st.*,c.c_id,c.c_name,sc.s_score FROM student stLEFT JOIN score sc ON sc.s_id=st.s_idINNER JOIN course c ON c.c_id =sc.c_id AND c.c_id="01"ORDER BY sc.s_score DESC LIMIT 1,2) t1UNION ALLSELE.