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https://issues.apache.org/jira/browse/CALCITE-4901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17449400#comment-17449400
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yanjing.wang commented on CALCITE-4901:
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Yes, The problem reproduces when NULL-ordering is not a problem.
I expect that the sql doesn't change in distributed query engine (such as
Spark, BigQuery).
> RelToSqlConverter adds redundant order by output column for the result sql
> --------------------------------------------------------------------------
>
> Key: CALCITE-4901
> URL: https://issues.apache.org/jira/browse/CALCITE-4901
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.26.0
> Environment: jdk8
> Reporter: yanjing.wang
> Priority: Major
>
> In RelToSqlConverterTest, I add the following case
> {code:java}
> @Test void testOrderByNotInSelectList() {
> String query = "select count(1)\n"
> + "from \"foodmart\".\"product\"\n"
> + "group by \"product_id\"\n"
> + "order by \"product_id\" desc\n";
> final String expected = "SELECT COUNT(1)\n"
> + "FROM \"foodmart\".\"product\"\n"
> + "GROUP BY \"product_id\"\n"
> + "ORDER BY \"product_id\" desc\n";
> sql(query).withBigQuery().ok(expected);
> }{code}
> But I get the actual sql is
> {code:java}
> SELECT COUNT(*), product_id
> FROM foodmart.product
> GROUP BY product_id
> ORDER BY product_id IS NULL DESC, product_id DESC {code}
> It has redundant product_id output column.
>
> Wage Through code, I find that the sort operator contains product_id. When I
> put a project with product_id only on the sort operator, the result sql has
> redundant subquery.
> {code:java}
> LogicalProject(EXPR$0=[$0])
> LogicalSort(sort0=[$1], dir0=[DESC])
> LogicalProject(EXPR$0=[$1], product_id=[$0])
> LogicalAggregate(group=[{0}], EXPR$0=[COUNT()])
> LogicalProject(product_id=[$1])
> JdbcTableScan(table=[[foodmart, product]]) {code}
> {code:java}
> SELECT `EXPR$0`
> FROM (SELECT COUNT(*) AS `EXPR$0`, product_id
> FROM foodmart.product
> GROUP BY product_id
> ORDER BY product_id IS NULL DESC, product_id DESC) AS t2 {code}
>
>
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