这两句hive sql有什么区别

[第一片心意]

select count(gender) as count
from bidp.user_cloud
group by gender
having gender=0



select count(gender=0) as count
from bidp.user_cloud



这两句sql有什么区别？？？

[wwt9527]

引用 楼主 第一片心意的回复:

select count(gender) as count
from bidp.user_cloud
group by gender
having gender=0



select count(gender=0) as count
from bidp.user_cloud



这两句sql有什么区别？？？

第一个是分组过滤后统计出数量，第二个是子查询实现的统计。第一个效率更快。