建表

create table user(
    `id` bigint unsigned not null auto_increment,
    `userid` bigint unsigned not null comment '用户id',
    `username` varchar(128) not null comment '用户名',
    `password` varchar(128) not null comment '密码',
    `wechatid` varchar(128) comment '微信号',
    `statu` tinyint not null comment '0普通用户 1超级管理员',
    `extra` longtext comment 'extra',
    primary key (`id`),
    unique key `unique_username` (`username`),
    unique key `unique_userid` (`userid`),
    key `key_statu` (`statu`)
)engine=innodb default charset=utf8 comment='用户表';

select @@global.tx_isolation;  //老版本查看事务隔离级别
select @@global.transaction_isolation;  //新版查看事务隔离级别
set global transaction isolation level read committed;  //设置全局事务隔离级别
set session transaction isolation level read committed;  //设置当前session事务隔离级别
use databese    //选择数据库
desc table      //查看标的结构
show tables     //查看当前数据库的所有表
drop table tablename    //删除表