CREATE TABLE student (
id INT(10) NOT NULL PRIMARY KEY ,
name VARCHAR(20) NOT NULL ,
sex VARCHAR(4) ,
birth YEAR,
department VARCHAR(20) ,
address VARCHAR(50)
);
CREATE TABLE score (
id INT(10) NOT NULL PRIMARY KEY AUTO_INCREMENT ,
stu_id INT(10) NOT NULL ,
c_name VARCHAR(20) ,
grade INT(10)
);
INSERT INTO student VALUES( 901,'张老大', '男',1985,'计算机系', '北京市海淀区');
INSERT INTO student VALUES( 902,'张老二', '男',1986,'中文系', '北京市昌平区');
INSERT INTO student VALUES( 903,'张三', '女',1990,'中文系', '湖南省永州市');
INSERT INTO student VALUES( 904,'李四', '男',1990,'英语系', '辽宁省阜新市');
INSERT INTO student VALUES( 905,'王五', '女',1991,'英语系', '福建省厦门市');
INSERT INTO student VALUES( 906,'王六', '男',1988,'计算机系', '湖南省衡阳市');
INSERT INTO score VALUES(NULL,901, '计算机',98);
INSERT INTO score VALUES(NULL,901, '英语', 80);
INSERT INTO score VALUES(NULL,902, '计算机',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, '计算机',70);
INSERT INTO score VALUES(NULL,904, '英语',92);
INSERT INTO score VALUES(NULL,905, '英语',94);
INSERT INTO score VALUES(NULL,906, '计算机',90);
INSERT INTO score VALUES(NULL,906, '英语',85);
SELECT * FROM student;
SELECT * FROM student LIMIT 1,3;
SELECT id,name,department FROM student;
SELECT * FROM student WHERE department="计算机系" or department="英语系";
SELECT * FROM student WHERE birth BETWEEN '1985' and '1990';
SELECT department , COUNT(1) 人数 FROM student GROUP BY department;
SELECT c_name , MAX(grade) FROM score GROUP BY c_name;
SELECT score.c_name , score.grade
FROM student
left join score on student.id = score.stu_id
WHERE student.name = "李四";
SELECT student.*, score.c_name , score.grade
FROM student
left join score on student.id = score.stu_id
SELECT student.`name` , SUM(score.grade) 总成绩
FROM student
left join score on student.id = score.stu_id
GROUP BY name
SELECT score.c_name , AVG(score.grade) FROM score GROUP BY score.c_name 平均分
SELECT student.*, score.c_name , score.grade
FROM student
left join score on student.id = score.stu_id
WHERE score.c_name = "计算机"
AND score.grade < 95;
SELECT student.*, score.c_name , score.grade
FROM student
left join score on student.id = score.stu_id
WHERE score.c_name = "计算机"
ORDER BY score.grade DESC
SELECT student.`name` , student.department , score.c_name , score.grade
FROM student
left join score on student.id = score.stu_id
WHERE student.`name` LIKE '张%'
OR student.`name` LIKE "王%"
SELECT student.`name` , ((select year(CURRENT_DATE))-student.birth) 年龄, student.department , score.c_name , score.grade
FROM student
left join score on student.id = score.stu_id
WHERE student.address LIKE "%北京%"