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https://issues.apache.org/jira/browse/CALCITE-2757?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16769367#comment-16769367
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Hongze Zhang commented on CALCITE-2757:
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Hi [~Krishnakant A], I'm wondering if the generated SQL like
[following|https://github.com/apache/calcite/pull/1000/files#diff-f985d2e1a0804e0c7250da49b53b9d85R278]
could work correctly on different SQL databases.
{code:sql}
SELECT \"product_id\", \"EXPR$1\"
FROM (SELECT \"product_id\", SUM(\"product_class_id\") OVER (PARTITION BY
\"product_id\" RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)
FROM \"foodmart\".\"product\") AS \"t\"
GROUP BY \"product_id\", \"EXPR$1\"
{code}
This requires the expression "SUM(\"product_class_id\") OVER (...)" generate
alias "EXPR$1" implicitly, I don't think it is a very common behavior for
popular SQL databases.
For example, If I run following SQL on MySQL database
{code:sql}
SELECT EXPR$1 FROM (SELECT id, MAX(rev)
FROM `docs`
GROUP BY id) t
{code}
, I'll get an error with message "Unknown column 'EXPR$1' in 'field list'".
> DISTINCT not being handled correctly in RelToSqlConverter
> ---------------------------------------------------------
>
> Key: CALCITE-2757
> URL: https://issues.apache.org/jira/browse/CALCITE-2757
> Project: Calcite
> Issue Type: Bug
> Components: core
> Reporter: KrishnaKant Agrawal
> Assignee: Julian Hyde
> Priority: Major
> Labels: pull-request-available
>
> SELECT DISTINCT sum( x ) OVER (PARTITION BY y) FROM t
> is valid (per SQL standard) but
> SELECT sum( x ) OVER (PARTITION BY y)
> FROM t
> GROUP BY sum( x ) OVER (PARTITION BY y)
> is not. For example, given the query
> select sum(deptno) over (partition by loc)
> from dept
> group by sum(deptno) over (partition by loc);
> Oracle gives
> ORA-00934: group function is not allowed here
> Therefore we should generate a sub-query, something like this:
> SELECT c1
> FROM (
> SELECT sum(deptno) OVER (PARTITION BY loc)
> FROM dept) AS t
> GROUP BY c1;
>
> This will be achieved by Adding a new condition for setting the needNew Flag
> in SqlImplemontor.Builder.builder() as true in case there are Aggregate
> Expressions being passed as Group By Keys.
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