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https://issues.apache.org/jira/browse/CALCITE-5677?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17717778#comment-17717778
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Tanner Clary commented on CALCITE-5677:
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[~julianhyde] [~dmsysolyatin] After reviewing a number of dialects, including
those Dmitry mentioned among others, I think we should remove the override in
{{SqlSubstringFunction}}. Up to this point, I have not found a dialect that
does not support comma-separated arguments for the {{SUBSTR}}/{{SUBSTRING}}
functions. I still think it could be helpful to potentially add some more tests
but as of now, I think the {{SUBSTRING(.. FROM .. FOR ..)}} signature should be
treated as an exception rather than the norm. Please let me know if either of
you have any other thoughts. Thanks!
> Remove unparseCall override in SqlSubstringFunction
> ---------------------------------------------------
>
> Key: CALCITE-5677
> URL: https://issues.apache.org/jira/browse/CALCITE-5677
> Project: Calcite
> Issue Type: Bug
> Reporter: Tanner Clary
> Assignee: Tanner Clary
> Priority: Major
> Labels: pull-request-available
>
> BigQuery's {{SUBSTR(value, position[, length])}} function currently gets
> translated to the standard {{SUBSTRING(value FROM position[ FOR length])}}.
> BigQuery expects the arguments to be comma-separated rather than the use of
> the {{FROM}} and {{FOR}} keywords.
> EXAMPLE: {{SUBSTR('hello', 2)}} would get translated to {{SUBSTRING('hello'
> FROM 2)}} which BigQuery does not recognize.
> Hive addresses this issue by adding onto {{HiveSqlDialect#unparseCall}}
> method. I believe BigQuery should do something similar to avoid this
> incorrect translation. The docs for the {{SUBSTR}} (and alias {{SUBSTRING}})
> function may be found
> [here|https://cloud.google.com/bigquery/docs/reference/standard-sql/string_functions#substr].
> I will open a PR shortly that implements my suggestion and adds a couple of
> tests as well.
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