'sql查询语法'

SELECT schema_name FROM information_schema.schemata;
查询所有数据库名

SELECT table_name FROM information_schema.tables WHERE table_schema=‘information_schema’;
查询数据库information_schema的所有表名

SELECT column_name FROM information_schema.columns WHERE table_name=‘TABLES’;
查询information_schema数据库下TABLES表的所有字段名

select title,author from text.content;
查询text数据库下content表中的所有title和author值

sql设置数据库语句

mysql获取某个数据库的所有表名
select TABLE_NAME from information_schema.tables 
where TABLE_SCHEMA="your database name"

mysql获取某个表的所有字段名  
select COLUMN_NAME from information_schema.COLUMNS 
where table_name = 'your_table_name';

用户表
create table `users`(
    `id` int(0) not null auto_increment,
    `username` varchar(50) not null UNIQUE, //名字//UNIQUE设置不重复
    `password` varchar(50) not null,        //密码
    `email` varchar(50) null,               //邮箱
    `nickname` varchar(50) not null,        //昵称
    `safepoint` varchar(50) null,           //安全问题
    `avatarimg` varchar(100) default '/images/default_avatar.jpg', //头像地址
    `reg_time` timestamp default current_timestamp(),              //创建时间
    `lastlogin_time` timestamp default current_timestamp(),     //最后登录时间
    `lastlogin_ip` varchar(255) null,                           //最后登录ip
    primary key(`id`)
);

INSERT INTO `mynews`.`tb_users`(
    `username`, `password`,`nick_name`
) VALUES (
    'zs','080687','mynews_12346'
);


新闻表
create table `tb_news`(
    `id` int(0) not null auto_increment,  //id
    `title` varchar(255) not null,        //标题
    `contents` text not null,             //内容
    `author` varchar(50) not null,        //作者
    `new_img` varchar(100) null,          //图片浏览图
    `add_time` timestamp default current_timestamp(),  //创建时间
    `hot` int(0) default 0,               //浏览量
    primary key(`id`)
);

评论表
create table `tb_discuss`(
    `id` int(0) not null auto_increment,
    `new_id` int(0) not null,               //新闻id
    `discuss_content` text not null,        //评论内容
    `discuss_user` varchar(50) not null,    //评论用户
    `discuss_time` timestamp default current_timestamp(),  //评论时间
    primary key(`id`)
);    


DELETE FROM `mynews` . `tb_users`;