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From "Zheng Shao (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-153) explain should give meaningful column names
Date Wed, 10 Dec 2008 23:18:44 GMT

    [ https://issues.apache.org/jira/browse/HIVE-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12655413#action_12655413
] 

Zheng Shao commented on HIVE-153:
---------------------------------

Basically, we should use meaningful names for internal names whenever possible, instead of
using numbers like 0, 1, 2, etc.


> explain should give meaningful column names
> -------------------------------------------
>
>                 Key: HIVE-153
>                 URL: https://issues.apache.org/jira/browse/HIVE-153
>             Project: Hadoop Hive
>          Issue Type: Improvement
>          Components: Query Processor
>            Reporter: Zheng Shao
>
> Currently explain uses numbers like "1" to represent the columns.
> It will be much better to print out the real name of the columns.
> hive> explain FROM table a SELECT a.country as b, count(1) as c WHERE a.ds='2008-12-09'
GROUP BY a.country;
> ...
>             Select Operator
>               expressions:
>                     expr: country
>                     type: string
>                     expr: ds
>                     type: string
>               Filter Operator
>                 predicate:
>                     expr: (1 = '2008-12-09')
>                     type: boolean
>                 Reduce Output Operator
>                   key expressions:
>                         expr: 0
>                         type: string
>                   sort order: +
>                   Map-reduce partition columns:
>                         expr: rand()
>                         type: double
>                   tag: -1
>                   value expressions:
>                         expr: 1
>                         type: int

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