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https://issues.apache.org/jira/browse/CALCITE-6219?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17812082#comment-17812082
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Julian Hyde commented on CALCITE-6219:
--------------------------------------
If a 'filter required' column is not filtered but it is in the SELECT clause,
*and the query is not top-level* it wouldn't error.
Because the obligation to filter the column would now fall on the consuming
query.
> Support SQL Validation for Tables with columns tagged as 'filter required'
> --------------------------------------------------------------------------
>
> Key: CALCITE-6219
> URL: https://issues.apache.org/jira/browse/CALCITE-6219
> Project: Calcite
> Issue Type: New Feature
> Reporter: Oliver Lee
> Assignee: Oliver Lee
> Priority: Major
>
> Suppose that a user's Table definitions come in with a tag on certain columns
> that indicates the the column is required to have a filter on it for all
> incoming queries.
>
> I would like to add support to validate that incoming queries satisfies the
> table condition.
> If all of the table's specified fields has a filter on it (present in a WHERE
> or HAVING clause for the query), then it will not error.
>
> ex.
> {{EMP}} table specifies that {{EMPNO}} requires a filter
>
> {{select * from emp where empno = 1}} -> No error
> {{select * from emp where ename = 'bob' -> Error}}
> {{select * from emp -> Error}}
>
> The validation would occur after the namespace validation in
> {{SqlValidatorImpl}} as a separate pass.
>
> I am envisioning that the full filter validation algorithm will form a couple
> of key steps
> * Scanning the catalog/schema/tables and determining which fields are
> tagged to always require filters
> * A pass through the SQL statement to see if a certain field needs to be
> filtered multiple times (potentially for CTE, joins? needs further
> investigation)
> * A pass through the SQL statement to discover filters on the statement
>
> In determining whether a {{WHERE}} or {{HAVING}} clause contains a certain
> field identifier, there will need to be a helper visitor for WHERE or HAVING
> SqlNodes to collect all of the SqlIdentifiers that could be nested within the
> {{operandList}}
>
> Special considerations:
> * joins
> * CTEs
> * subqueries
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