[jira] [Commented] (CALCITE-3440) RelToSqlConverter does not properly alias ambiguous ORDER BY

["Julian Hyde (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-3440?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16958099#comment-16958099 ] 

Julian Hyde commented on CALCITE-3440:
--------------------------------------

Agreed, this is a bug. Calcite would have to know how the target dialect interprets the expression in the ORDER BY clause, but in all dialects I know, an identifier in the ORDER BY clause is taken as an alias in preference to an unqualified column name.  That information is in {{SqlConformance}} (e.g. {{isSortByAlias()}} and {{isSortByAliasObscures()}}).

> RelToSqlConverter does not properly alias ambiguous ORDER BY
> ------------------------------------------------------------
>
>                 Key: CALCITE-3440
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3440
>             Project: Calcite
>          Issue Type: Bug
>            Reporter: Steven Talbot
>            Priority: Major
>
> Best illustrated by a test that will fail if you put it in RelToSqlConverterTest
>  
> {code:java}
> @Test public void testSelectQueryWithAmbiguousOrderByClause() {
>   String query = "select \"product_id\" as \"p\", \"net_weight\" as \"product_id\"  from \"product\" order by 1";
>   final String expected = "SELECT \"product_id\" AS \"p\", \"net_weight\" AS \"product_id\"\n"
>           + "FROM \"foodmart\".\"product\"\n"
>           + "ORDER BY \"product\".\"product_id\"";
>   sql(query).ok(expected);
> }{code}
>  
> Kind of a strange case, but basically you select a column, alias it, and order by it. And then you select something else and alias it as that column. RelToSqlConverter will ORDER BY just the column, unaliased ("product_id"), which, at least on HyperSQL and MySQL where I tested, ends up ordering by the aliased expression ("net_weight" as "product_id") vs the column  (either "product"."product_id" or "p" would work in this case).



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