1.創建student和score表
CREATE? TABLE? student (
id? INT(10)? NOT NULL? UNIQUE? PRIMARY KEY? ,
name? VARCHAR(20)? NOT NULL ,
sex? VARCHAR(4)? ,
birth? YEAR,
department? VARCHAR(20) ,
address? VARCHAR(50)?
);
創建score表。SQL代碼如下：
CREATE? TABLE? score (
id? INT(10)? NOT NULL? UNIQUE? PRIMARY KEY? AUTO_INCREMENT ,
stu_id? INT(10)? NOT NULL ,
c_name? VARCHAR(20) ,
grade? INT(10)
);
2.為student表和score表增加記錄
向student表插入記錄的INSERT語句如下：
INSERT INTO student VALUES( 901,'張老大', '男',1985,'計算機系', '北京市海淀區');
INSERT INTO student VALUES( 902,'張老二', '男',1986,'中文系', '北京市昌平區');
INSERT INTO student VALUES( 903,'張三', '女',1990,'中文系', '湖南省永州市');
INSERT INTO student VALUES( 904,'李四', '男',1990,'英語系', '遼寧省阜新市');
INSERT INTO student VALUES( 905,'王五', '女',1991,'英語系', '福建省廈門市');
INSERT INTO student VALUES( 906,'王六', '男',1988,'計算機系', '湖南省衡陽市');
向score表插入記錄的INSERT語句如下：
INSERT INTO score VALUES(NULL,901, '計算機',98);
INSERT INTO score VALUES(NULL,901, '英語', 80);
INSERT INTO score VALUES(NULL,902, '計算機',65);
INSERT INTO score VALUES(NULL,902, '中文',88);
INSERT INTO score VALUES(NULL,903, '中文',95);
INSERT INTO score VALUES(NULL,904, '計算機',70);
INSERT INTO score VALUES(NULL,904, '英語',92);
INSERT INTO score VALUES(NULL,905, '英語',94);
INSERT INTO score VALUES(NULL,906, '計算機',90);
INSERT INTO score VALUES(NULL,906, '英語',85);
1.查詢student表的所有記錄?
select * from student ;
2.查詢student表的第2條到4條記錄?
查詢連續的多行記錄(第n~m行)select * from table1 limit n-1,m-n+1;select * from student limit 1,3;
3.從student表查詢所有學生的學號（id）、姓名（name）和院系（department）的信息
select id,name,department from student;
4.從student表中查詢計算機系和英語系的學生的信息?
select * from student where department = '英語系' or department = ' 計算機系';
5.從student表中查詢年齡18~22歲的學生信息?
select * from student where birth < 2003 and birth > 1999 ;
簡單做個減法 當前時間 - 18 or 22? 要注意大小。
6.從student表中查詢每個院系有多少人?
select department,count(1) from student? group by department;
7.從score表中查詢每個科目的最高分?
select c_name,max(grade) from score group by c_name;
8.查詢李四的考試科目（c_name）和考試成績（grade）?
select c_name,grade
??? -> from score where stu_id=
??? -> (select id from student
??? -> where name = '李四');
9.用連接的方式查詢所有學生的信息和考試信息?
select student.id,name,sex,birth,department,address,c_name,grade from student,score where student.id = score.stu_id;
10.計算每個學生的總成績?
select student.id,name,sum(grade) from student,score where student.idd= score.stu_id group by id;
11.計算每個考試科目的平均成績?
SELECT?c_name,AVG(grade)?FROM?score?GROUP?BY?c_name;
12.查詢計算機成績低于95的學生信息?
select * from student where id in (select stu_id from score where c_name ='計算機' and grade < 95);
13.查詢同時參加計算機和英語考試的學生的信息?
select * from student where id = any(select stu_id from score where stu_id in ( select stu_id from score where c_name = '計算機') and c_name = '英語');
14.將計算機考試成績按從高到低進行排序?
SELECT stu_id, grade? FROM score WHERE c_name= '計算機' ORDER BY grade DESC;
15.從student表和score表中查詢出學生的學號，然后合并查詢結果?
SELECT?id??FROM?student? UNION SELECT?stu_id??FROM?score;
16.查詢姓張或者姓王的同學的姓名、院系和考試科目及成績?
mysql> SELECT student.id, name,sex,birth,department, address, c_name,grade
??? -> FROM student, score
??? -> WHERE
??? ->? (name LIKE? '張%'? OR name LIKE? '王%')
??? -> and student.id=score.stu_id ;
17.查詢都是湖南的學生的姓名、年齡、院系和考試科目及成績
SELECT student.id, name,sex,birth,department, address, c_name,grade FROM student, score WHERE address LIKE '湖南%'?? AND student.id=score.stu_id;
