摘要：show databases; use php_edu; set names utf8; show tabels; desc test; create table test ( id int primary key not null a
show databases;
use php_edu;
set names utf8;
show tabels;
desc test;
create table test
(
id int primary key not null auto_increment COMMENT '用户主键' ,
name varchar(30) COMMENT '用户名称' ,
email varchar(40) COMMENT '用户邮箱',
pass varchar(40) COMMENT '用户密码',
age int(3) COMMENT '用户年龄',
sex int(1) COMMENT '用户性别',
status int(1) COMMENT '用户状态' ,
create_time int(20) ,
UNIQUE KEY `name` (`name`)
)ENGINE = InnoDB DEFAULT CHARSET=utf8;
insert into `test` values (null,'张三分','zsf@qq.com',sha('123456'),88,0,0,1550405626);
insert into `test` values (null,'张三分111','zsf@qq.com',sha('123456'),88,0,0,1550405626);
insert into `test` values (null,'梅超风','zsf@qq.com',sha('123456'),88,1,0,1550405626);
insert into `test` values (null,'梅超风1111','zsf@qq.com',sha('123456'),88,1,0,1550405626);
select * from `test`;
select count(*) as res from `test`;
select name,sex from `test` where `sex` = '1';
select concat(name,sex) as list from `test` where `sex` = 0 limit 1;
select concat_ws('---',name,sex) as list from `test` where `sex` = 0 ;
update `test` SET `name` = '欧阳克' WHERE `sex`=0;
update `test` SET `name` = '天山童姥' WHERE `sex`=1 limit 1;
delete from `test` where `id` = 2 ;
delete from `test` where `name` = '天山童姥' limit 1;
insert into `test` values (null,'朱元璋111','zsf@qq.com',sha('123456'),88,0,0,1550405626),
(null,'陈友谅456','zsf@qq.com',sha('123456'),88,0,0,1550405626);
alter table `test` drop `id`;
alter table `test` add `id` mediumint(5) primary key not null auto_increment first;
select * from `test` where `id` >=0;
批改老师：查无此人批改时间：2019-02-18 09:29:50
老师总结：update `test` SET `name` = '欧阳克' WHERE `sex`=0; 修改条件，最好能准确些。。 性别等于0，修改的数据会很多。
delete from `test` where `name` = '天山童姥' limit 1; 删除的条件，也最好准确些，如果有两个天山童姥，你根本不知道删除的是哪个。
继续加油。
