-- 31、查詢所有教師和同學的name、sex和birthday.
SELECT TNAME AS '名字',TSEX  AS SEX,TBIRTHDAY AS BIRTHDAY FROM TEACHER
UNION
SELECT SNAME AS '名字',SSEX AS SEX,SBIRTHDAY AS BIRTHDAY FROM STUDENT;

-- 32、查詢所有“女”教師和“女”同學的name、sex和birthday.
SELECT TNAME AS '名字',TSEX  AS SEX,TBIRTHDAY AS BIRTHDAY FROM TEACHER
WHERE TSEX='女'
UNION
SELECT SNAME AS '名字',SSEX AS SEX,SBIRTHDAY AS BIRTHDAY FROM STUDENT
WHERE SSEX='女';

-- *自連線* 注意此題 注意此題 注意此題 注意此題 注意此題 注意此題
-- 33、查詢成績比該課程平均成績低的同學的成績表。
SELECT * FROM SCORE A
WHERE DEGREE<(SELECT AVG(DEGREE) FROM SCORE B WHERE B.CNO=A.CNO);
-- *自連線* 注意此題 注意此題 注意此題 注意此題 注意此題 注意此題

-- 34、查詢所有任課教師的Tname和Depart.
SELECT TNAME,DEPART FROM TEACHER;

-- 35  查詢所有未講課的教師的Tname和Depart. 
SELECT TNAME,DEPART FROM TEACHER
WHERE TNO NOT IN (SELECT TNO FROM COURSE
WHERE CNO IN (SELECT CNO FROM COURSE
WHERE CNO IN (SELECT CNO FROM SCORE)));

-- 36、查詢至少有2名男生的班號。
SELECT SCLASS FROM STUDENT
WHERE SSEX='男'
GROUP BY SCLASS
HAVING COUNT(SSEX)>1;

-- 37、查詢Student表中不姓“王”的同學記錄。
SELECT SNAME FROM STUDENT
WHERE SNAME NOT LIKE'王%';

-- 38、查詢Student表中每個學生的姓名和年齡。
SELECT SNAME,(YEAR(NOW())-YEAR(SBIRTHDAY)) AS YEARS FROM STUDENT;

-- 39、查詢Student表中最大和最小的Sbirthday日期值。
SELECT MAX(SBIRTHDAY),MIN(SBIRTHDAY) FROM STUDENT;

-- 40、以班號和年齡從大到小的順序查詢Student表中的全部記錄。
SELECT * FROM STUDENT
ORDER BY SCLASS DESC,SBIRTHDAY DESC;

-- 41、查詢“男”教師及其所上的課程。
SELECT * FROM COURSE
WHERE TNO IN(SELECT TNO FROM TEACHER WHERE TSEX='男');

-- 42、查詢最高分同學的Sno、Cno和Degree列。
SELECT SNO,CNO,DEGREE FROM SCORE
WHERE SNO=(SELECT SNO FROM SCORE
WHERE DEGREE=(SELECT MAX(DEGREE) FROM SCORE));

-- 43、查詢和“李軍”同性別的所有同學的Sname.
SELECT SNAME FROM STUDENT
WHERE SSEX=(SELECT SSEX FROM STUDENT
WHERE SNAME='李軍');

-- 44、查詢和“李軍”同性別並同班的同學Sname.
SELECT SNAME FROM STUDENT
WHERE SSEX=(SELECT SSEX FROM STUDENT
WHERE SNAME='李軍')
AND SCLASS=(SELECT SCLASS FROM STUDENT
WHERE SNAME='李軍')
AND SNAME NOT LIKE '李軍';

-- 45、查詢所有選修“計算機導論”課程的“男”同學的成績表
SELECT SNO,DEGREE FROM SCORE
WHERE CNO=(SELECT CNO FROM COURSE WHERE CNAME='計算機導論')
AND SNO IN(SELECT SNO FROM STUDENT WHERE SSEX='男');