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https://issues.apache.org/jira/browse/TRAFODION-1673?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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liu ming updated TRAFODION-1673:
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Comment: was deleted
(was: It can be first implemented using sub-query, that is, to replace each
WITH clause by a sub query. (RenamedTable)
CTE mentioned by QiFan is a great idea, and we can set it as a final goal. To
meet the functional requirement, we can simply use subquery in the first
iteration.)
> Implement the WITH clause in Trafodion SQL for simple use cases
> ---------------------------------------------------------------
>
> Key: TRAFODION-1673
> URL: https://issues.apache.org/jira/browse/TRAFODION-1673
> Project: Apache Trafodion
> Issue Type: New Feature
> Components: sql-cmp
> Reporter: Hans Zeller
> Assignee: liu ming
>
> We keep running into queries that use a WITH clause to define a temporary
> view that can be used once or multiple times in a FROM clause in the query.
> For non-recursive queries, the WITH clause could probably be handled very
> similar to a view. When it is defined, we create an in-memory view
> descriptor, containing the name and the definition. When it is used in a FROM
> clause, we could go through a code path similar to that of a view - bind the
> (temporary) view text and substitute it in the query. The fix could probably
> be handled entirely in the binder.
> This JIRA is *not* about recursive queries, those would require a lot more
> effort, involving many components in addition to the binder.
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