11. Management of tables and libraries

One . Create data table

create table t_student
(
    id int primary key auto_increment,
    name varchar(10) not null,
    age int,
    sex varchar(8) not null default ' Woman ',
    address varchar(100),
    height double,
    birthday date
)charset=utf8;

Two . Add data

insert into t_student (name,age,sex,birthday,height)
values (' Fan Tingting ',18,' Woman ','1998-12-4',170.6);

insert into t_student(name,age,sex)
values(null,10,' male ');

insert into t_student 
values(null,' Cheng Rui ',19,' male ',' nanjing ',176.6,now())

3、 ... and . Modify data sheet

1. Add columns

alter table t_student add weight double;

2. Modify column type

alter table t_student modify name varchar(250);

3. Change column names

alter table t_student change sex gender varchar(8);

4. Modify the name of the table

alter table t_student rename student;

rename table student to t_student;

Four . Delete table

drop table if exists user;

5、 ... and . Truncation table

truncate table emp;

6、 ... and . Create a library

create database if not exists shop charset utf8;

7、 ... and . Delete Library

drop database if exists shop;