在包含 a、b、c、d、e、f、g、h、i、j、k 列的表上，我得到：
select * from misty order by a limit 25;
Time: 302.068 ms
和：
select c,b,j,k,a,d,i,g,f,e,h from misty order by a limit 25;
Time: 1258.451 ms
有没有办法让按列选择的速度一样快？
更新：
表上没有索引，新创建的
这是解释分析，似乎没有太大帮助：
explain analyze select * from misty order by a limit 25;
Limit (cost=43994.40..43994.46 rows=25 width=190) (actual time=404.958..404.971 rows=25 loops=1)
-> Sort (cost=43994.40..45731.11 rows=694686 width=190) (actual time=404.957..404.963 rows=25 loops=1)
Sort Key: a
Sort Method: top-N heapsort Memory: 28kB
-> Seq Scan on misty (cost=0.00..24390.86 rows=694686 width=190) (actual time=0.013..170.945 rows=694686 …