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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 Calcite’s 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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