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From "Jesus Camacho Rodriguez (JIRA)" <j...@apache.org>
Subject [jira] [Created] (HIVE-14431) Recognize COALESCE as CASE and extend CASE simplification to cover more cases
Date Thu, 04 Aug 2016 19:36:20 GMT
Jesus Camacho Rodriguez created HIVE-14431:
----------------------------------------------

             Summary: Recognize COALESCE as CASE and extend CASE simplification to cover more
cases
                 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: Jesus Camacho Rodriguez


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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