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From "Jihoon Son (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (TAJO-186) Improve column resolving method
Date Sat, 21 Sep 2013 01:52:52 GMT

    [ https://issues.apache.org/jira/browse/TAJO-186?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13773675#comment-13773675
] 

Jihoon Son commented on TAJO-186:
---------------------------------

+1
I've verified with 'mvn install'.
                
> Improve column resolving method
> -------------------------------
>
>                 Key: TAJO-186
>                 URL: https://issues.apache.org/jira/browse/TAJO-186
>             Project: Tajo
>          Issue Type: Bug
>          Components: planner/optimizer
>            Reporter: Hyunsik Choi
>            Assignee: Hyunsik Choi
>             Fix For: 0.2-incubating
>
>         Attachments: TAJO-186_2.patch, TAJO-186.patch
>
>
> The current column resolving method (LogicalPlanner::createFieldEval) usually finds columns
from relations in the current query block. If not found, it tries to find columns from other
query blocks.
> However, this way cannot resolve some cases. Please take a look at the below example:
> {noformat}
> select col1 as rank from table1 order by rank
> {noformat}
> In the above case, the column 'rank' cannot be found in any relation. So, in this case,
we currently use LogicalPlan::findColumnFromChildNode method to resolve columns from a child
node.
> But, this way cannot resolve a column 'total' in the below cases:
> {noformat}
> select ..., sum(col1) as total ... having total > 1
> {noformat}
> Resolving columns should also consider the current node's output schema.

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