1.創(chuàng)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(chuàng)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(yǔ)句如下：

INSERT INTO student VALUES( 901,'張老大', '男',1985,'計(jì)算機(jī)系', '北京市海淀區(qū)');

INSERT INTO student VALUES( 902,'張老二', '男',1986,'中文系', '北京市昌平區(qū)');

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(yǔ)系', '遼寧省阜新市');

INSERT INTO student VALUES( 905,'王五', '女',1991,'英語(yǔ)系', '福建省廈門(mén)市');

INSERT INTO student VALUES( 906,'王六', '男',1988,'計(jì)算機(jī)系', '湖南省衡陽(yáng)市');

向score表插入記錄的INSERT語(yǔ)句如下：

INSERT INTO score VALUES(NULL,901, '計(jì)算機(jī)',98);

INSERT INTO score VALUES(NULL,901, '英語(yǔ)', 80);

INSERT INTO score VALUES(NULL,902, '計(jì)算機(jī)',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(jì)算機(jī)',70);

INSERT INTO score VALUES(NULL,904, '英語(yǔ)',92);

INSERT INTO score VALUES(NULL,905, '英語(yǔ)',94);

INSERT INTO score VALUES(NULL,906, '計(jì)算機(jī)',90);

INSERT INTO score VALUES(NULL,906, '英語(yǔ)',85);

1.查詢(xún)student表的所有記錄?

select * from student ;

2.查詢(xún)student表的第2條到4條記錄?

查詢(xún)連續(xù)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(xún)所有學(xué)生的學(xué)號(hào)（id）、姓名（name）和院系（department）的信息

select id,name,department from student;

4.從student表中查詢(xún)計(jì)算機(jī)系和英語(yǔ)系的學(xué)生的信息?

select * from student where department = '英語(yǔ)系' or department = ' 計(jì)算機(jī)系';

5.從student表中查詢(xún)年齡18~22歲的學(xué)生信息?

select * from student where birth < 2003 and birth > 1999 ;

簡(jiǎn)單做個(gè)減法 當(dāng)前時(shí)間 - 18 or 22? 要注意大小。

6.從student表中查詢(xún)每個(gè)院系有多少人?

select department,count(1) from student? group by department;

7.從score表中查詢(xún)每個(gè)科目的最高分?

select c_name,max(grade) from score group by c_name;

8.查詢(xún)李四的考試科目（c_name）和考試成績(jī)（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(xún)所有學(xué)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(jì)算每個(gè)學(xué)生的總成績(jī)?

select student.id,name,sum(grade) from student,score where student.idd= score.stu_id group by id;

11.計(jì)算每個(gè)考試科目的平均成績(jī)?

SELECT?c_name,AVG(grade)?FROM?score?GROUP?BY?c_name;

12.查詢(xún)計(jì)算機(jī)成績(jī)低于95的學(xué)生信息?

select * from student where id in (select stu_id from score where c_name ='計(jì)算機(jī)' and grade < 95);

13.查詢(xún)同時(shí)參加計(jì)算機(jī)和英語(yǔ)考試的學(xué)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(jì)算機(jī)') and c_name = '英語(yǔ)');

14.將計(jì)算機(jī)考試成績(jī)按從高到低進(jìn)行排序?

SELECT stu_id, grade? FROM score WHERE c_name= '計(jì)算機(jī)' ORDER BY grade DESC;

15.從student表和score表中查詢(xún)出學(xué)生的學(xué)號(hào)，然后合并查詢(xún)結(jié)果?

SELECT?id??FROM?student? UNION SELECT?stu_id??FROM?score;

16.查詢(xún)姓張或者姓王的同學(xué)的姓名、院系和考試科目及成績(jī)?

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(xún)都是湖南的學(xué)生的姓名、年齡、院系和考試科目及成績(jī)

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;

總結(jié)

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