研究一条distinct+order by+limit的SQL执行过程，发现limit影响排序结果的彩蛋
假设有如下表：mysql> select * from tab;+----+------+| id | col1 |+----+------+| 1 | 2 || 2 | 2 || 3 | 5 || 4 | 3 || 5 | 3 || 6 | 4 |+----+------+6 rows in set (0.01 sec...
