hive union all 问题
20191025
-
（1） hive中使用union all要保证联结的
字段类型一致 -
（2）要保持
字段名称一致，否则报错Schema of both sides of union should match.
insert into table mytable1
select
acol1 as mycol1,
acol2 as mycol2
from atable
union all
selest
bcol1 as mycol1,
null as mycol2 -- 即使是null,也要取别名
from btable
- 也可以都不取别名
insert into table mytable1
select
acol1,
acol2
from atable
union all
selest
bcol1,
null
from btable