mysql知识点

1、分页查询要order by id，这样才能用到索引。

2、当数据量很大时，查询后面的页码偏移量很大，消耗的时间相应增多，如每页十行，查询1001页，偏移为 limit 10000,10 以下的sql语句就不适用了

select * from content order by id desc limit 10000,10;

可以使用子查询来改善：

select * from content where id<=(select id from content order by id desc limit 10000, 1) order by id desc limit 10;

或者连接查询：

select t1.* from content t1 join (select id from content order by id desc limit 10000, 1) as t2 on t1.id<t2.id order by t1.id desc limit 10;