[jira] [Commented] (CALCITE-7613) Support multi-operand CONCAT operator

["Mihai Budiu (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-7613?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18090371#comment-18090371 ] 

Mihai Budiu commented on CALCITE-7613:
--------------------------------------

CONCAT_WS accepts multiple arguments.

> Support multi-operand CONCAT operator
> -------------------------------------
>
>                 Key: CALCITE-7613
>                 URL: https://issues.apache.org/jira/browse/CALCITE-7613
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.42.0
>            Reporter: Yu Xu
>            Assignee: Yu Xu
>            Priority: Minor
>              Labels: pull-request-available
>             Fix For: 1.43.0
>
>
> Currently, Calcite's CONCAT operator (the || string concatenation operator) is defined as a SqlBinaryOperator, which restricts it to exactly two operands at the RexNode level. 
> This limitation forces users to manually construct nested CONCAT calls or use workarounds when dealing with multiple string concatenations.
> When attempting to concatenate more than two strings:
> {code:java}
>   -- Desired SQL (currently fails at RexNode construction)
>   SELECT CONCAT('Hello', ' ', 'World', '!');
>   -- Or using the || operator
>   SELECT 'Hello' || ' ' || 'World' || '!';   {code}
> If you try to construct  3+ operands it would error out:
> {code:java}
> wrong operand count 3 for ||
>  {code}
> Mainstream databases today, such as PostgreSQL and Oracle, support multi-argument `CONCAT`.
> postgresql：[https://onecompiler.com/postgresql/44sufvv78]
> oracle：https://onecompiler.com/plsql/44sufwevp



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