mysql 的 limit 优化

[guyeuro]

下面两个语句

select phone from user  where id >(select id from user limit 3000000,1) order by id limit 0,10;

select phone from user  order by id limit 3000001,10;

测试多次，第一个总是比第二个好， 索引都是主键 id 为何会有区别？

[guyeuro]

顶顶顶！