mysql and sqlite

select * from mytable limit 2,3;

去掉mytable 里前两条数据 查出接下来的三条数据

或者说从2+1条开始查3条数据

select * from mytable order by id desc ;

在mytable 按id降序排序

修改密码！！！

呈上一位前辈的博客：

http://www.jb51.net/article/98270.htm

超级管理员密码格式：不是password 是 authentication_string

数据库sqlite:

https://www.cnblogs.com/gccbuaa/p/7283907.html

外键语法：

select * from userInfo left outer join equipment on userInfo.iduser=equipment.userid

或：

select * from userInfo left join equipment on userInfo.iduser=equipment.userid

或内连接：

select * from userInfo join equipment on userInfo.iduser=equipment.userid

select * from userInfo inner join equipment on userInfo.iduser=equipment.userid

交叉连接：

select attackSpeed from userInfo cross join equipment

三、交叉连接 cross join

1.概念：没有 WHERE 子句的交叉联接将产生连接所涉及的表的笛卡尔积。第一个表的行数乘以第二个表的行数等于笛卡尔积结果集的大小。

SQL语句：select * from student cross join course

假设我们在此时给这条SQL加上WHERE子句的时候比方SQL:select * from student cross join course where student.ID=course.ID

此时将返回符合条件的结果集。结果和inner join所看到的运行结果一样。

on userInfo.iduser=equipment.userid相当于条件

右连接、全然外连接不支持：

Error while executing SQL query on database 'mygame': RIGHT and FULL OUTER JOINs are not currently supported

select qty from Item join UserInfo on userInfo.userId=Item.userId where itemType='木头'

Trying to add Fill (UnityEngine.UI.Image) for graphic rebuild while we are already inside a graphic

slider没赋初值