[jira] [Commented] (CALCITE-2649) Allow RelBuilder to create field references to aliased relations without knowing the size of the stack

["Stamatis Zampetakis (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-2649?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16671284#comment-16671284 ] 

Stamatis Zampetakis commented on CALCITE-2649:
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I don't want to know the stack depth and I don't want to specify the inputCount when I am creating field references with aliases. 

I am just building conditions before/after joins so as you correctly guessed I am calling RelBuilder#field(inputCount,alias,fieldName) method with either inputCount=1 or inputCount=2. However, in order to pass the correct inputCount I need to know if the join is performed or not. Furthermore, to use inputCount correctly I need to be aware of the internals of the RelBuilder like for example that when the join is applied the stack size decreases. 

I think that it would be convenient to just call RelBuilder#field(alias,fieldName) in every case instead of RelBuilder#field(inputCount,alias,fieldName). Assuming that RelBuilder#field(alias,fieldName) is able to search anywhere in the stack, I don't see a huge benefit of having RelBuilder#field(inputCount,alias,fieldName) as part of the public API but maybe there is a good reason for its existence.

> Allow RelBuilder to create field references to aliased relations without knowing the size of the stack
> ------------------------------------------------------------------------------------------------------
>
>                 Key: CALCITE-2649
>                 URL: https://issues.apache.org/jira/browse/CALCITE-2649
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.17.0
>            Reporter: Stamatis Zampetakis
>            Assignee: Julian Hyde
>            Priority: Minor
>              Labels: beginner, newbie
>             Fix For: 1.18.0
>
>
> As of [CALCITE-1523|https://issues.apache.org/jira/browse/CALCITE-1523] it is possible to create field references to aliased relations anywhere in the stack. However the respective field method requires to pass as a parameter the inputCount (i.e., size of the stack). This is not very convenient since clients of RelBuilder are obliged to track the size of the stack (leading to the uneseccary creation of Wrapper classes).



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