SQL查询语言练习

USE master GO IF EXISTS (SELECT * FROM sysdatabases WHERE name='MyStudentInfoManage')DROP DATABASE  MyStudentInfoManage         --删除数据库GO CREATE DATABASE MyStudentInfoManage        --创建数据库GO USE MyStudentInfoManageGO --学生表IF EXISTS(SELECT * FROM sysobjects WHERE name='Student')DROP TABLE Student        --删除表GO CREATE TABLE Student(   --  Student(S#,Sname,Sage,Ssex) 学生表      S# INT NOT NULL PRIMARY KEY ,     --学号     Sname NVARCHAR(20) NOT NULL,      --姓名     Sage INT NOT NULL ,               --年龄     Ssex CHAR(2) NOT NULL             --性别                             );--教师表IF EXISTS(SELECT * FROM sysobjects WHERE name='Teacher')DROP TABLE TeacherGO CREATE TABLE Teacher(  --Teacher(T#,Tname) 教师表  T# INT NOT NULL PRIMARY KEY,  Tname NVARCHAR(20) NOT NULL  );--课程表IF EXISTS(SELECT * FROM sysobjects WHERE name='Course')DROP TABLE CourseGO CREATE TABLE  Course(   --Course(C#,Cname,T#) 课程表    C# INT NOT NULL PRIMARY KEY ,   Cname NVARCHAR(20) NOT NULL ,   T# INT NOT NULL  REFERENCES dbo.Teacher(T#)  );--成绩表IF EXISTS(SELECT * FROM sysobjects WHERE name='SC')DROP TABLE SCGO CREATE TABLE SC(        --SC(S#,C#,score) 成绩表         S# INT NOT NULL REFERENCES dbo.Student(S#),        C# INT NOT NULL REFERENCES dbo.Course(C#),        Score INT NOT NULL,        CONSTRAINT FK_Student_Course PRIMARY  KEY(S#,C#)    --学号和课程号同时座位            );----------------------------------------------------------------------插入测试数据到数据表(Student)中--------------------------------------------DELETE FROM dbo.Student;INSERT INTO dbo.Student        ( S#, Sname, Sage, Ssex )VALUES  ( 001, -- S# - int          N'张三', -- Sname - nvarchar(20)          20, -- Sage - int          '男'  -- Ssex - char(2)          )          INSERT INTO dbo.Student        ( S#, Sname, Sage, Ssex )VALUES  ( 002, -- S# - int          N'李四', -- Sname - nvarchar(20)          21, -- Sage - int          '男'  -- Ssex - char(2)          ) INSERT INTO dbo.Student        ( S#, Sname, Sage, Ssex )VALUES  ( 003, -- S# - int          N'王五', -- Sname - nvarchar(20)          22, -- Sage - int          '女'  -- Ssex - char(2)          ) INSERT INTO dbo.Student        ( S#, Sname, Sage, Ssex )VALUES  ( 004, -- S# - int          N'周六', -- Sname - nvarchar(20)          18, -- Sage - int          '女'  -- Ssex - char(2)          )                          ------------------------------------------------------------插入数据到教师表(Teacher)中----------------------------------------------------------DELETE FROM dbo.Teacher;          INSERT INTO dbo.Teacher        ( T#, Tname )VALUES  ( 01, -- T# - int          N'叶平'  -- Tname - nvarchar(20)          )                ------------------------------------------------------------------插入数据到课程表中-------------------------------------------------------------DELETE FROM dbo.Course;INSERT INTO dbo.Course        ( C#, Cname, T# )VALUES  ( 001, -- C# - int          N'语文', -- Cname - nvarchar(20)          01  -- T# - int          )              INSERT INTO dbo.Course        ( C#, Cname, T# )VALUES  ( 002, -- C# - int          N'数学', -- Cname - nvarchar(20)          01  -- T# - int          )                         INSERT INTO dbo.Course        ( C#, Cname, T# )VALUES  ( 0003, -- C# - int          N'英语', -- Cname - nvarchar(20)          01  -- T# - int          )                                            --------------------------插入数据到成绩表（SC）中-----------------------------------------------------------------------------------------------  DELETE FROM dbo.SC;              INSERT INTO dbo.SC        ( S#, C#, Score )VALUES  ( 001, -- S# - int          001, -- C# - int          90  -- Score - int          )