use message_board;

drop table if exists users;

create table users(

id int unsigned primary key auto_increment,

username char(20) unique ,

password char(30) not null,

token char(30) not null unique,

birthday date,

phone_number int unsigned unique ,

email char(30),

create_datetime datetime

default current_timestamp not null

);

desc users;

ALTER TABLE users

Change user_name username char(20);

ALTER TABLE users

MODIFY COLUMN token char(30) not null unique;

delete from users where token = 'bbc';

insert into

users(user_name, password, token)

values(

'Jack',

'123456',

'safesedese');

select * from users;

PREPARE createUser

FROM 'insert into users(

user_name, password, token)

VALUE (?, ?, ?)';

# set three variables for prepared statement.

SET @a = 'AAAA';

SET @b = '132131';

SET @c = 'bbc';

EXECUTE createUser USING @a, @b, @c;

DEALLOCATE PREPARE createUser;

PREPARE testMultipleStatement1

FROM 'insert into users(

user_name, password, token)

VALUE (?, ?, ?)';