[jira] [Commented] (CALCITE-4362) Unable to parse queries that use BigQuery pseudo columns _PARTITIONDATE/_PARTITIONTIME

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

    [ https://issues.apache.org/jira/browse/CALCITE-4362?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17431445#comment-17431445 ] 

Stamatis Zampetakis commented on CALCITE-4362:
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I completely agree with [~julianhyde].

I might have done something like that in a previous project I was working on. Vaguely I remember I drew inspiration from the way rolled up columns are handled in [SqlValidatorImpl.expandStar|https://github.com/apache/calcite/blob/bf962b86d9c27ca429ae71bf75a2acdca06eee91/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java#L635]. The trick is to find the table to which the column belongs and the latter should implement an appropriate interface (such as [Table.isRolledUp|https://github.com/apache/calcite/blob/bf962b86d9c27ca429ae71bf75a2acdca06eee91/core/src/main/java/org/apache/calcite/schema/Table.java#L71] ) to be able to tell if a column is a system column or not.

For that use-case, I think I ended up sub-classing {{SqlValidatorImpl}} and overloading [SqlValidatorImpl.addToSelectList|https://github.com/apache/calcite/blob/bf962b86d9c27ca429ae71bf75a2acdca06eee91/core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java#L2067] as an attempt to not modify Calcite. I guess if want to make this part of the core it will be easier.

> Unable to parse queries that use BigQuery pseudo columns _PARTITIONDATE/_PARTITIONTIME
> --------------------------------------------------------------------------------------
>
>                 Key: CALCITE-4362
>                 URL: https://issues.apache.org/jira/browse/CALCITE-4362
>             Project: Calcite
>          Issue Type: Bug
>          Components: babel
>            Reporter: Justin Swett
>            Assignee: Julian Hyde
>            Priority: Major
>
> BigQuery supports partitioned tables using pseudo columns "_PARTITIONDATE"
> e.g. The following table has two columns you can select from but also partitions the data by creation date
> {code:java}
> CREATE or REPLACE TABLE #{table} (            
>   transaction_id STRING, 
>   order_date DATE )
> PARTITION BY _PARTITIONDATE
> {code}
>  
> The following queries cannot be validated 
> {code:java}
> select * from #{table} where _PARTITIONDATE = '2020-11-03' ;
> -- OR
> select * from #{table} where _PARTITIONTIME = '2020-11-03' ;{code}



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