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https://issues.apache.org/jira/browse/CALCITE-4702?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17456016#comment-17456016
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Julian Hyde commented on CALCITE-4702:
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Let's use the terminology 'literal' rather than 'constant'.
The solution seems to be particular to boolean literals. What about literals of
other types, e.g. CHAR? Postgres disallows {{GROUP BY 'a'}} (giving the error
"ERROR: non-integer constant in GROUP BY") but bizarrely allows boolean
literals (e.g. {{{}GROUP BY TRUE{}}}). So I have a feeling that the current
solution will fail on Postgres for any types other than {{BOOLEAN}} and
{{{}INTEGER{}}}.
Should the method {{SqlDialect.supportsGroupByBooleanConstant}} be generalized
to {{supportsGroupByLiteral}} and be made to return false in not just Redshift
but the whole Postgres family? I think that would be prudent. Also add a test
{{testGroupByDateLiteralSimple}} that is a clone of
{{{}testGroupByBooleanConstantSimple{}}}.
+1 with those changes (replace literal with constant, add test for Postgres
with a date literal, and do whatever changes are necessary in the dialect to
make that test pass)
> Error when executing query with GROUP BY constant via JDBC adapter
> ------------------------------------------------------------------
>
> Key: CALCITE-4702
> URL: https://issues.apache.org/jira/browse/CALCITE-4702
> Project: Calcite
> Issue Type: Bug
> Components: core, jdbc-adapter
> Affects Versions: 1.27.0
> Reporter: Stamatis Zampetakis
> Assignee: Soumyakanti Das
> Priority: Major
> Labels: pull-request-available
> Time Spent: 1h 10m
> Remaining Estimate: 0h
>
> The following functionally equivalent SQL queries are accepted by Calcite and
> produce a valid plan
> {noformat}
> select avg(salary) from employee group by true
> select avg(salary) from employee group by 'a'
> {noformat}
> but they may fail if they are executed via the JDBC adapter since not all
> DBMS allow grouping by constants expressions. Moreover, what works for one
> may not work for the other.
> +Examples+
> The {{GROUP BY TRUE}} query works in Postgres, and MySQL but fails in
> Redshift with the following exception:
> {noformat}
> com.amazon.redshift.util.RedshiftException: ERROR: non-integer constant in
> GROUP BY
> {noformat}
> The {{GROUP BY 'a'}} query works in MySQL but fails in Postgres with the
> following exception:
> {noformat}
> ERROR: non-integer constant in GROUP BY
> {noformat}
> +Edit:+
> The {{GROUP BY}} constant is similar to {{GROUP BY ()}} "nothing" but as
> shown in the discussion below they are not equivalent. There is a nice [blog
> post|https://blog.jooq.org/2018/05/25/how-to-group-by-nothing-in-sql/]
> listing some limitations of various DBMS when it comes to {{GROUP BY ()}}.
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