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From "John Sichi (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HIVE-972) support views
Date Thu, 14 Jan 2010 22:57:54 GMT

    [ https://issues.apache.org/jira/browse/HIVE-972?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12800406#action_12800406

John Sichi commented on HIVE-972:

One other point for reviewers:

If you do CREATE VIEW v(x,y) AS SELECT a+1,b+2 FROM t

then we'll store the expanded view def as SELECT `_c0` AS `x`,`_c1` AS `y` FROM (SELECT `t`.`a`+1,`t`.`b`+2
FROM `t`) `v`

As a result, if hive ever changes its convention for generating anonymous expression names
(_c0, _c1, ...), such stored view definitions will break.

The only way I can think of to avoid this is to implement SQL:200n's column-alias-by-position
construct , e.g.

(SELECT `t`.`a`+1,`t`.`b`+2 FROM `t`) AS `v`(`x`,`y`)

(similar to what was done for LATERAL VIEW).

> support views
> -------------
>                 Key: HIVE-972
>                 URL: https://issues.apache.org/jira/browse/HIVE-972
>             Project: Hadoop Hive
>          Issue Type: New Feature
>          Components: Metastore, Query Processor
>            Reporter: Namit Jain
>            Assignee: John Sichi
>         Attachments: HIVE-972.1.patch
> Hive currently does not support views. 
> It would be a very nice feature to have.

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