Hive中case when的两种语法

总结一下：两种表达方式是等效的
方法一：

case
when tb1.os = 'android' then 'android'
when tb1.os = 'ios' then 'iPhone'
else 'PC'
end as os

方法二：

case tb1.os
when 'android' then 'android'
when 'ios' then 'iPhone'
else 'PC'
end as os