select * from ( select id,name,rownum as num from table ) where num<=10 这句话效率很慢.
而 select * from ( select id,name,rownum as num from table ) where num<=100 却很快.有些莫名,期盼高人指点
而 select * from ( select id,name,rownum as num from table ) where num<=100 却很快.有些莫名,期盼高人指点
看看执行计划就知道为什么慢了