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Posted to issues@hive.apache.org by "Remus Rusanu (JIRA)" <ji...@apache.org> on 2017/02/02 09:52:51 UTC

[jira] [Assigned] (HIVE-14431) Recognize COALESCE as CASE

     [ https://issues.apache.org/jira/browse/HIVE-14431?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Remus Rusanu reassigned HIVE-14431:
-----------------------------------

    Assignee: Remus Rusanu  (was: Jesus Camacho Rodriguez)

> Recognize COALESCE as CASE
> --------------------------
>
>                 Key: HIVE-14431
>                 URL: https://issues.apache.org/jira/browse/HIVE-14431
>             Project: Hive
>          Issue Type: Improvement
>          Components: CBO
>    Affects Versions: 2.2.0
>            Reporter: Jesus Camacho Rodriguez
>            Assignee: Remus Rusanu
>         Attachments: HIVE-14431.01.patch, HIVE-14431.2.patch, HIVE-14431.patch
>
>
> Transform:
> {code}
> (COALESCE(a, '')  = '') OR
>            (a = 'A' AND b = c)  OR
>            (a = 'B' AND b = d) OR
>            (a = 'C' AND b = e) OR
>            (a = 'D' AND b = f) OR
>            (a = 'E' AND b = g) OR
>            (a = 'F' AND b = h)
> {code}
> into:
> {code}
> (a='') OR
>            (a is null) OR
>            (a = 'A' AND b = c)  OR
>            (a = 'B' AND b = d) OR
>            (a = 'C' AND b = e) OR
>            (a = 'D' AND b = f) OR
>            (a = 'E' AND b = g) OR
>            (a = 'F' AND b = h)
> {code}
> With complex queries, this will lead us to factor more predicates that could be pushed to the TS.



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