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From "huo.zhu" <zhuhuoc...@gmail.com>
Subject Column Name in Nested Select of Hive Join Operator
Date Tue, 15 Jul 2014 10:32:04 GMT
Hi,

 

I recently find a problem about column name in Hive join operator.  The HQL
is like this

 

select * from  -- possible column names are  key,  value

(

    select * from  -- possible column names are   tb_1.key,  tb_1.value,
tb_2.key,   tb_2.value

    (

        select key ,value

        from test_tb_1

    ) tb_1

 

JOIN

 

    (

        select key ,value

        from test_tb_2

) tb_2

 

    on tb_1.key = tb_2.key

 

) tb_1_2

 

Why the outer select has only two columns?

 I check the explain output , and find these two columns are from tb_2,  is
this an Optimization in Hive Or a Bug?

 

 


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