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https://issues.apache.org/jira/browse/CALCITE-5044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17510502#comment-17510502
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Xurenhe commented on CALCITE-5044:
----------------------------------
Yes, I agree with you.
We could define a switch[{*}removeOrderByConstantKey]{*} in *SqlDialect*
whether remove constant keys in order-by.
Please review this [PR-2749|[https://github.com/apache/calcite/pull/2749], if
you have a time.|https://github.com/apache/calcite/pull/2749],]
Thanks a lot.
> OrderBy constant executing RelToSql ambiguously
> -----------------------------------------------
>
> Key: CALCITE-5044
> URL: https://issues.apache.org/jira/browse/CALCITE-5044
> Project: Calcite
> Issue Type: Improvement
> Reporter: Xurenhe
> Assignee: Xurenhe
> Priority: Major
> Attachments: image-2022-03-17-21-45-22-988.png
>
>
>
> There is ambiguous in the rel-to-sql's converter when meeting `order by
> constant `.
> Here is an example:
> {code:java}
> @Test void testOderByConstant() {
> final Function<RelBuilder, RelNode> relFn = b -> b
> .scan("EMP")
> .project(b.literal(1), b.field(1), b.field(2))
> .sort(RelCollations.of(ImmutableList.of(
> new RelFieldCollation(0), new RelFieldCollation(1))))
> .project(b.field(2), b.field(1))
> .build();
> final String expected = "";
> relFn(relFn).ok(expected);
> } {code}
> Return sql:
> {code:java}
> SELECT "JOB", "ENAME"
> FROM "scott"."EMP"
> ORDER BY 1, "ENAME" {code}
> But, `ORDER BY 1` may mean 'sort by the first column in the select list'
> because of SqlConformance#isSortByOrdinal.
>
> I keep this the same semantics, by apply the rule of
> `CoreRules#SORT_REMOVE_CONSTANT_KEYS`
> Should the rel_to_sql's converter support it natively?
> *CODE:*
> https://github.com/wojustme/calcite/blob/6ad04e85875d9202e592a78cca8db807c5bde362/core/src/test/java/org/apache/calcite/rel/rel2sql/RelToSqlConverterTest.java#L1601
>
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