45道经典SQL题练习(四)

-- 31、查询所有教师和同学的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、查询所有“女”教师和“女”同学的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';

-- *自连接* 注意此题 注意此题 注意此题 注意此题 注意此题 注意此题
-- 33、查询成绩比该课程平均成绩低的同学的成绩表。
SELECT * FROM SCORE A
WHERE DEGREE<(SELECT AVG(DEGREE) FROM SCORE B WHERE B.CNO=A.CNO);
-- *自连接* 注意此题 注意此题 注意此题 注意此题 注意此题 注意此题

-- 34、查询所有任课教师的Tname和Depart.
SELECT TNAME,DEPART FROM TEACHER;

-- 35  查询所有未讲课的教师的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、查询至少有2名男生的班号。
SELECT SCLASS FROM STUDENT
WHERE SSEX='男'
GROUP BY SCLASS
HAVING COUNT(SSEX)>1;

-- 37、查询Student表中不姓“王”的同学记录。
SELECT SNAME FROM STUDENT
WHERE SNAME NOT LIKE'王%';

-- 38、查询Student表中每个学生的姓名和年龄。
SELECT SNAME,(YEAR(NOW())-YEAR(SBIRTHDAY)) AS YEARS FROM STUDENT;

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

-- 40、以班号和年龄从大到小的顺序查询Student表中的全部记录。
SELECT * FROM STUDENT
ORDER BY SCLASS DESC,SBIRTHDAY DESC;

-- 41、查询“男”教师及其所上的课程。
SELECT * FROM COURSE
WHERE TNO IN(SELECT TNO FROM TEACHER WHERE TSEX='男');

-- 42、查询最高分同学的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、查询和“李军”同性别的所有同学的Sname.
SELECT SNAME FROM STUDENT
WHERE SSEX=(SELECT SSEX FROM STUDENT
WHERE SNAME='李军');

-- 44、查询和“李军”同性别并同班的同学Sname.
SELECT SNAME FROM STUDENT
WHERE SSEX=(SELECT SSEX FROM STUDENT
WHERE SNAME='李军')
AND SCLASS=(SELECT SCLASS FROM STUDENT
WHERE SNAME='李军')
AND SNAME NOT LIKE '李军';

-- 45、查询所有选修“计算机导论”课程的“男”同学的成绩表
SELECT SNO,DEGREE FROM SCORE
WHERE CNO=(SELECT CNO FROM COURSE WHERE CNAME='计算机导论')
AND SNO IN(SELECT SNO FROM STUDENT WHERE SSEX='男');