[jira] [Comment Edited] (CALCITE-5013) Unparse SqlSetOperator should be retained parentheses when generating SQL for UNION ... LIMIT

["Jiajun Xie (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-5013?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17501085#comment-17501085 ] 

Jiajun Xie edited comment on CALCITE-5013 at 3/4/22, 12:02 AM:
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Hello, [~julianhyde]. Would you review this pr again? https://github.com/apache/calcite/pull/2724


was (Author: jiajunbernoulli):
Hello, [~julianhyde]. Would you review this pr again? https://issues.apache.org/jira/browse/CALCITE-5013

> Unparse SqlSetOperator should be retained  parentheses when generating SQL for UNION ... LIMIT
> ----------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-5013
>                 URL: https://issues.apache.org/jira/browse/CALCITE-5013
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>            Reporter: Jiajun Xie
>            Priority: Major
>
> - In standard SQL, the operand of union should not have limit  or order by.So parse will fail in SqlParserTetest#testLimitUnion and SqlParserTetest#OrderUnion.
>  - When users use parentheses, most engines allow it. See the discussion:CALCITE-1892.   
> For simple example, parentheses control the scope of the limit
> {code:java}
> select "product_id" from "product"
> union all
> (select "product_id" from "product" limit 10){code}
> unparseBinarySyntax will miss parentheses, this change will affect semantics
> {code:java}
> SELECT \"product_id\" FROM \"foodmart\".\"product\" 
> UNION ALL 
> SELECT \"product_id\" FROM \"foodmart\".\"product\" 
> FETCH NEXT 10 ROWS ONLY  -- Affect semantics{code}



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