下面两个HIVE query做同一件事情,请问那个query更efficient?假设在Map Reduce的 frame work 下 Query 1: select id, count(distinct value) values from table1 group by id; Query 2: select a.id, sum(1) values from (select distinct id, value from table1 )a group by a.id ; 另外请有哪本书或视频讲HIVE的query efficiency吗