麻烦做一下sql题，直接写出sql就可以了，很简单的。

1.
SELECT *
FROM STUDENT
WHERE SDEPT='信息系' AND SSEX='女' AND SAGE<=21
2.
SELECT SNAME
FROM STUDENT W
WHERE EXISTS(SELECT *
FROM STUDENT
WHERE SNAME='wang' AND W.SNO>SNO AND W.SAGE3.
SELECT SNAME,SAGE
FROM STUDENT
WHERE SSEX='男'AND SAGE>(SELECT SAGE
FROM STUDENT
WHERE SSEX='女')
4.
SELECT CNAME,COUNT(*)
FROM COURSE JOIN SCG ON COURSE.CNO=SCG.CNO
GROUP BY CNAME

5
SELECT CNO,COUNT(*) 人数
FROM SCG
GROUP BY CNO
HAVING COUNT(*)>10
ORDER BY 2 DESC,1
6
DELETE FROM SCG WHERE SNO=(SELECT SNO FROM STUDENT WHERE SNAME='WANG')
7
INSERT INTO STUDENT VALUES('200200146','王飞','男',20,'信息系')
8
UPDATE SCG SET GRADE=GRADE*1.05
WHERE CNO=3' AND GRADE<=75
9
SELECT *
INTO Student_bak
FROM STUDENT

确实挺简单的，为啥不自己写。