loading1. SELECT *
FROM Student 结果：
2. SELECT Sname 姓名,Sage 年龄
FROM Student
WHERE Sdept='计算机系' 结果：
3. SELECT Sno 学号,Cno 课程号,Grade 成绩
FROM SC
WHERE Grade BETWEEN 70 AND 80
4. SELECT Sname 姓名,Sage 年龄
FROM Student
WHERE Sdept='计算机系' AND Sage>=18 AND Sage<=20 AND Ssex='男'
5. SELECT MAX(Grade) 最高分数
FROM SC
WHERE Cno='c01'
6. SELECT MAX(Sage) 最大年龄,MIN(Sage) 最小年龄
FROM Student
WHERE Sdept='计算机系'
7. SELECT Sdept 系名,COUNT(*) 学生人数
FROM Student GROUP BY Sdept
8. SELECT Cname 课程名,COUNT(*) 选课门数,MAX(Grade) 最高分
FROM Course,SC GROUP BY Cname
9. SELECT Sno 学号,COUNT(*) 选课门数,SUM(Grade) 总成绩
FROM SC GROUP BY Sno
ORDER BY'选课门数' ASC
10. SELECT Sno 学号,SUM(Grade) 总成绩
FROM SC GROUP BY Sno
HAVING SUM(Grade)>200
10.
CREAT TABLE BOOK（
Snobook nchar(6) PRIMARY KEY, Snamebook nvarchar(30) NBOT NULL, Writer char(10) NOT NULL, Time smalldatetime, Price numeric(3,1) )
CREAT TABLE BOOKSHOP(
Snoshop nchar(6) PRIMARY KEY, Snameshop nvarchar(30) NOT NULL, Tel char（8）CHECK(Tel =0 AND Tel <=9), Place nchar(40), Snoemail char(6) )
CREAT TABLE BOOKSELL（ Snobook nchar(6) NOT NULL,
Snoshop nchar(6) NOT NULL, Selltime smalltime NOT NULL, Snosell tinyint,
PRIMARY KEY (Snobook, Snoshop, Selltime),
FOREIGN KEY (Snobook) REFERENCES BOOK(Snobook), FOREIGN KEY (Snoshop) REFERENCES BOOK(BOOKSHOP) ) 11.
ALTER TABLE BOOK ADD Nomber int
ADD CONSTRAINT DF-Nomber CHECK (Nomber>1000) 12.
ALTER TABLE BOOKSHOP DROP COLUMN Tel 13.
ALTER TABLE BOOKSELL
ALTER COLUMN Snosell int