前面學習了MySQL的語句的基本用法，這里就開始做一些MySQL練習，這套題目一共45題，屬於比較簡單的，初學先試着做這個。
參考鏈接：https://www.cnblogs.com/SJP666/p/4665605.html 感謝博主
一、先創建幾個要用的庫表
create database ZuoYe; -- 創建數據庫 use ZuoYe; -- 使用數據庫
#創建幾個庫表 create table Student -- 學生表 ( Sno char(3) NOT NULL Primary key , -- 學號 ，設為主鍵，不允許空值 Sname char(8) NOT NULL, -- 學生姓名 Ssex char(2)NOT NULL, -- 學生性別 Sbirthday datetime, -- 學生出生年月 Class char(5) -- 學生所在班級 ); create table Teacher -- 教師表 ( Tno char(3)NOT NULL primary key, -- 教工編號設為主鍵 Tname char(4)NOT NULL, -- 教工姓名 Tsex char(2)NOT NULL, -- 教工性別 Tbirthday datetime, -- 教工出生年月 Prof char(6), -- 職稱 Depart varchar(10)NOT NULL -- 教工所在部門 ) create table Course -- 課程表 ( Cno char(5) NOT NULL Primary key , -- 課程號設為主鍵 Cname varchar(10) NOT NULL, -- 課程名稱 Tno char(3) NOT NULL references Teacher(Tno) -- 教工編號設為外鍵 ) create table Score -- 成績表 ( Sno char(3) NOT NULL references Student(Sno), -- 學號設為外碼 Cno char(5) NOT NULL references Course(Cno), -- 課程號設為外碼 Degree Decimal(4,1), -- 成績 primary key(Sno,Cno) -- 學號和課程號設為聯合主鍵 )
二、插入數據
insert into Student values(108,'曾華','男','1977-09-01','95033'); insert into Student values(105,'匡明','男','1975-10-02','95031'); insert into Student values(107,'王麗','女','1976-01-23','95033'); insert into Student values(101,'李軍','男','1976-02-20','95033'); insert into Student values(109,'王芳','女','1975-02-10','95031'); insert into Student values(103,'陸君','男','1974-06-03','95031'); insert into Teacher values(804,'李誠','男','1958-12-02','副教授','計算機系'); insert into Teacher values(856,'張旭','男','1969-03-12','講師','電子工程系'); insert into Teacher values(825,'王萍','女','1972-05-05','助教','計算機系') ; insert into Teacher values(831,'劉冰','女','1977-08-14','助教','電子工程系'); insert into Course values('3-105','計算機導論',825); insert into Course values('3-245','操作系統',804); insert into Course values('6-166','數字電路',856); insert into Course values('9-888','高等數學',831); insert into Score values(103,'3-245',86); insert into Score values(105,'3-245',75); insert into Score values(109,'3-245',68); insert into Score values(103,'3-105',92); insert into Score values(105,'3-105',88); insert into Score values(109,'3-105',76); insert into Score values(101,'3-105',64); insert into Score values(107,'3-105',91); insert into Score values(108,'3-105',78); insert into Score values(101,'6-166',85); insert into Score values(107,'6-166',79); insert into Score values(108,'6-166',81);
這個插入語句寫的真是粗糙啊，一條條插入。。。懶得改了
三、查詢練習（重點）
select * from student; select * from teacher; select * from course; select * from score;
1~5題：
-- 1、查詢Student表中的所有記錄的Sname、Ssex和Class列。 select sname,ssex,class from student; -- 2、 查詢教師所有的單位即不重復的Depart列 select distinct depart from teacher; -- 3、 查詢Student表的所有記錄。 select * from student; -- 4、 查詢Score表中成績在60到80之間的所有記錄 select * from score where degree between 60 and 80; -- 5、 查詢Score表中成績為85，86或88的記錄。 select * from score where degree in (85,86,88);
6~10題：
-- 6、 查詢Student表中“95031”班或性別為“女”的同學記錄。 select * from student where class = '95031' or Ssex='女'; -- 7、 以Class降序查詢Student表的所有記錄。 select * from student order by class desc; -- 8、 以Cno升序、Degree降序查詢Score表的所有記錄。 select * from score ORDER BY cno asc,degree desc; -- 9、 查詢“95031”班的學生人數。 select count(1) from student where class = '95031'; -- 10、 查詢Score表中的最高分的學生學號和課程號。（子查詢或者排序） select sno,cno from score where degree = (select max(degree) from score); -- 10.1查詢Score表中除了每門課程最高分的學生學號和課程號。（子查詢或者排序） select sno,cno from score where degree not in (select max(degree) from score group by cno)
11~12題：
-- 11、 查詢每門課的平均成績。 select cno,avg(degree) from score group by cno; -- 12、查詢Score表中至少有5名學生選修的並以3開頭的課程的平均分數。 select cno,avg(degree) from score where cno in (select cno from score group by cno HAVING count(1) > 5 ) and cno like '3%'; -- 13、查詢分數大於70，小於90的Sno列。 select sno from score where degree between 70 and 90; -- 14、查詢所有學生的Sname、Cno和Degree列。 select student.sname,score.cno , score.degree from score left join student on student.sno = score.sno; -- 15、查詢所有學生的Sno、Cname和Degree列。 select score.sno,course.cname,score.degree from score left join course on course.cno = score.cno; -- 16、查詢所有學生的Sname、Cname和Degree列。 select student.sname,course.cname,score.degree from score left join student on student.sno = score.sno left join course on score.cno = course.cno; -- 17、 查詢“95033”班學生的平均分。 select avg(degree) from score where sno in (select sno from student where class = 95033)
create table Grade(Low int ,Upp int,Rank char(1)) select *from Grade; insert into Grade values(90,100,'A'); insert into Grade values(80,89,'B'); insert into Grade values(70,79,'C'); insert into Grade values(60,69,'D'); insert into Grade values(0,59,'E');
第十八題：這題不會做，都沒做過
-- 現查詢所有同學的Sno、Cno和rank列。 select sno,cno,rank from score,grade where degree between low and upp
-- 19、 查詢選修“3-105”課程的,並且成績高於“109”號同學成績的所有同學的記錄。 select * from score where cno = '3-105' and degree > (select degree from score where sno=109 and cno='3-105')
-- 21、 查詢成績高於學號為“109”、課程號為“3-105”的成績的所有記錄。 select * from score where degree > (select degree from score where sno = 109 and cno = '3-105') -- 22、查詢和學號為108的同學同年出生的所有學生的Sno、Sname和Sbirthday列。 select * from student; select sno,sname,sbirthday from student where year(sbirthday) =(select year(sbirthday) from student where sno = 108) -- 23、查詢“張旭“教師任課的學生成績。 select * from teacher where tname = '張旭'; select * from course ; select * from score where cno = (select cno from course where tno = (select tno from teacher where tname = '張旭')) -- 24、查詢選修某課程的同學人數多於5人的教師姓名。 select cno,count(1) from score group by cno HAVING count(1) > 5; select tname from teacher where tno = (select tno from course where cno = (select cno from score group by cno HAVING count(1) > 5)) -- 25、查詢95033班和95031班全體學生的記錄。 select * from student where Class in (95033,95031); -- 26、 查詢存在有85分以上成績的課程Cno. select distinct cno from score where Degree > 85 -- 27、查詢出“計算機系“教師所教課程的成績表。 select tno from teacher where depart = '計算機系'; select cno from course where tno in (select tno from teacher where depart = '計算機系'); select * from score where cno in (select cno from course where tno in (select tno from teacher where depart = '計算機系')); -- 29、查詢選修編號為“3-105“課程且成績至少高於一個選修編號為“3-245”的同學的Cno、Sno和Degree,並按Degree從高到低次序排序。 select * from score where cno = '3-105' and degree > any(select degree from score where cno = '3-245'); #這個其實跟min（degree）是一樣的 -- 30、查詢選修編號為“3-105”且成績高於選修編號為“3-245”課程的同學的Cno、Sno和Degree. select cno,sno,degree from score where cno = '3-105' and degree > all(select degree from score where cno = '3-245'); #這個其實是個max（degree）一樣的
第33題之前也不會做，這種類型的都不太會
-- 31、 查詢所有教師和同學的name、sex和birthday. select sname,ssex,sbirthday from student union ALL select tname,tsex,tbirthday from teacher; -- 32、查詢所有“女”教師和“女”同學的name、sex和birthday. select sname,ssex,sbirthday from student where ssex = '女' union ALL select tname,tsex,tbirthday from teacher where tsex = '女'; -- 33、 查詢成績比該課程平均成績低的同學的成績表。 select * from score s1 where degree < (select avg(degree) from score s2 group by cno having s1.cno = s2.cno)
-- 34、 查詢所有任課教師的Tname和Depart select * from teacher; select DISTINCT cno from score; select tno from course where cno in (select DISTINCT cno from score); select tname,depart from teacher where tno in (select tno from course where cno in (select DISTINCT cno from score)) -- 34、 查詢所有任課教師的Tname和Depart select * from teacher; select DISTINCT cno from score; select tno from course where cno in (select DISTINCT cno from score); select tname,depart from teacher where tno in (select tno from course where cno in (select DISTINCT cno from score)); -- 36、查詢至少有2名男生的班號。 select class from student where ssex='男' group by class having count(1) >=2 -- 37、查詢Student表中不姓“王”的同學記錄。 select * 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) 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 class,year(now())-year(sbirthday);
-- 41、查詢“男”教師及其所上的課程。 select tno from teacher where tsex = '男'; 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 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 class = (select class from student where sname = '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 * from course ; select s.*,c.cname,s2.ssex from score as s left join course as c on s.cno = c.cno left join student as s2 on s.sno = s2.sno; select * from (select s.*,c.cname,s2.ssex from score as s left join course as c on s.cno = c.cno left join student as s2 on s.sno = s2.sno) as temp where temp.ssex = '男' and temp.cname = '計算機導論'