#新建数据库
CREATE DATABASE school;
#查看数据库
SHOW DATABASES;
#查看当前新建数据库
SHOW CREATE DATABASE school;
#换库
USE school;
#删除新建的库
DROP DATABASE school;
#查询当前所在的数据库
SELECT DATABASE();
#新建数据库表
CREATE TABLE student(
#设置主键，同时设置自动增长
sID INT PRIMARY KEY AUTO_INCREMENT,
studentName VARCHAR(10),
phone VARCHAR(20),
address VARCHAR(200)
);
#添加数据
INSERT INTO student(studentName,phone,address) VALUES(\'郭子豪\',\'17744673401\',\'黄河路13号\'),
(\'李振烨\',\'15638431234\',\'花园路15号\'),
(\'陈富国\',\'12345676543\',\'东风路12号\');
#查询表结构
DESC student;
#查询数据表内容
SELECT * FROM student;
#修改数据表
UPDATE student SET studentname=\'张凡\'WHERE sID=1;
UPDATE student SET address=\'中国\'WHERE address=\'东风路12号\';
UPDATE student SET phone=\'10086\';
#删除数据表
DELETE FROM student WHERE sid=3;
DELETE FROM student;
#删除表
TRUNCATE TABLE student;
#删除主键约束
INSERT INTO student VALUES(NULL,\'郭子豪\',\'12345678\',\'俄罗斯\');
INSERT INTO student VALUES(\'郭子豪\',\'12306\',\'俄罗斯\');
UPDATE student SET phone=\'12306\'WHERE sid=4;
ALTER TABLE student DROP PRIMARY KEY;
#修改约束
ALTER TABLE student MODIFY sid INT;
#显示表结构
DESC student;
#添加主键 自动增长
ALTER TABLE student ADD PRIMARY KEY(sid);