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Posted to issues@calcite.apache.org by "Julian Hyde (JIRA)" <ji...@apache.org> on 2016/11/29 20:50:58 UTC
[jira] [Resolved] (CALCITE-1472) Support CROSS/OUTER APPLY syntax
[ https://issues.apache.org/jira/browse/CALCITE-1472?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Julian Hyde resolved CALCITE-1472.
----------------------------------
Resolution: Fixed
Fix Version/s: 1.11.0
Fixed in http://git-wip-us.apache.org/repos/asf/calcite/commit/8355a252 (not including concise table function syntax, which is covered by CALCITE-1490). Thanks for the PR, [~jark]!
> Support CROSS/OUTER APPLY syntax
> --------------------------------
>
> Key: CALCITE-1472
> URL: https://issues.apache.org/jira/browse/CALCITE-1472
> Project: Calcite
> Issue Type: New Feature
> Reporter: Jark Wu
> Assignee: Julian Hyde
> Fix For: 1.11.0
>
>
> The CROSS/OUTER APPLY is very similar to CROSS JOIN and OUTER JOIN. The difference is that the APPLY operator is used to invoke a table-valued function. This is not a standard SQL syntax , but introduced from MS SQL Server [1].
> The APPLY operator can be expressed by Calciteās LATERAL TABLE . That means the
> SELECT MyTable.*, t.s FROM MyTable CROSS APPLY split(MyTable.a)) AS t(s)
> corresponds to :
> SELECT MyTable.*, t.s FROM MyTable, LATERAL TABLE(split(MyTable.a)) AS t(s)
> and
> SELECT MyTable.*, t.s FROM MyTable OUTER APPLY split(MyTable.a)) AS t(s)
> corresponds to:
> SELECT MyTable.*, t.s FROM MyTable LEFT JOIN LATERAL TABLE(split(MyTable.a)) AS t(s) ON TRUE
> The ON TRUE part is necessary for LEFT JOIN, but it's trivial for users. That's why I'm introducing "CROSS/OUTER APPLY" which will simplify the SQL a lot.
> As the APPLY can be expressed by LATERAL, so the only thing we need to touch is the Parser (see [2] and search FLINK to find the modification).
> [1] https://technet.microsoft.com/en-us/library/ms175156(v=sql.105).aspx
> [2] https://github.com/wuchong/flink/blob/60812e51156ec9fa6088154d2f6dea8c1ff9ac17/flink-libraries/flink-table/src/main/codegen/templates/Parser.jj
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