sql查询练习（一）

sql查询练习（一）

创建练习使用表

使用sql_test数据库

# create database sql_test;
use sql_test;

创建学生表

Student包含（Sid,Sname,Sage,Ssex四个字段）

create table Student(
  Sid varchar(10),
  Sname varchar(10),
  Sage datetime,
  Ssex varchar(10)
);

创建教师表

Teacher包含(Tid,Tname两个字段）

create table Teacher(
  Tid varchar(10),
  Tname varchar(10)
);

创建按课程表

Course包含（Cid,Cname,Tid三个字段）

create table Course(
  Cid varchar(10),
  Cname varchar(10),
  Tid varchar(10)
);

创建成绩表

SC包含（Sid,Cid,score三个字段)

create table SC(
  Sid varchar(10),
  Cid varchar(10),
  score decimal(18,1)
);

向表中插入数据

向学生表中插入数据

insert into Student values('01' , '赵雷' , '1900-01-01' , '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('09' , '张三' , '2017-12-20' , '女');
insert into Student values('10' , '李四' , '2017-12-25' , '女');
insert into Student values('11' , '李四' , '2017-12-30' , '女');
insert into Student values('12' , '赵六' , '2017-01-01' , '女');
insert into Student values('13' , '孙七' , '2018-01-01' , '女');

向教师表中插入数据

insert into Teacher values ('01','张三');
insert into Teacher values ('02','李四');
insert into Teacher values ('03','王五');

向课程表中插入数据

insert into Course values('01' , '语文' , '02');
insert into Course values('02' , '数学' , '01');
insert into Course values('03' , '英语' , '03');

向成绩表中插入数据

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);

验证

select * from Student;

select * from Teacher;

select * from Course;

select * from SC;