如何删除查询中列名中的表名？

Question

我有一个hive查询，如下所示：

set hive.cli.print.header=true;
select x1, x2, x3 from table1
union all
select x1, x2, x3 from table2

问题是，hive会自动为列名添加新的表名，因此结果中的列名如下所示：

_u1.x1  _u1.x2  _u1.x3

我不想要“_u1”。如何将列名保持为：

x1  x2  x3

Answer 1

select x1, x2, x3 from
(select x1, x2, x3 from table1
union all
select x1, x2, x3 from table2) as test;

<强> 之前：

select order_id,order_date from orders limit 1
union all
select order_id,order_date from orders limit 1;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
_u1.order_id    _u1.order_date
1   2013-07-25 00:00:00.0
1   2013-07-25 00:00:00.0

<强> 后：

select order_id, order_date from
(select order_id,order_date from orders limit 1
union all
select order_id,order_date from orders limit 1) as test;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
order_id    order_date
1   2013-07-25 00:00:00.0
1   2013-07-25 00:00:00.0