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https://issues.apache.org/jira/browse/PHOENIX-1749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14484081#comment-14484081
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James Taylor commented on PHOENIX-1749:
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bq. If using RowProjector for order by position, can we use
projector.getColumnProjector(index-1).getExpression() directly to get the
expression
Yes
bq. If yes, why setting columnRef for Visitor.
The TrackOrderPreservingExpressionCompiler is doing additional work that you'll
be bypassing by getting the expression directly from the RowProjector. The
minor refactoring I mentioned is to ensure that this additional work is being
done for this new code path.
> ORDER BY should support ordinal position as well as expression
> --------------------------------------------------------------
>
> Key: PHOENIX-1749
> URL: https://issues.apache.org/jira/browse/PHOENIX-1749
> Project: Phoenix
> Issue Type: Bug
> Reporter: Serhiy Bilousov
> Assignee: Alicia Ying Shu
> Attachments: PHOENIX-1749-v1.patch, PHOENIX-1749.patch
>
>
> In postgreSQL (and many others DBs) you can specify not only column name for
> the ORDER BY but column number (position in SELECT part) as well as column
> alias.
> see:
> http://www.postgresql.org/docs/9.4/static/queries-order.html
> http://www.postgresql.org/docs/9.4/static/sql-select.html#SQL-GROUPBY
> Adding such support would be very helpful and sometimes necessary.
> I can provide real queries example if required but basically we want
> something like this
> given query
> SELECT a, b, TRUNC(current_date(),'HOUR') AS date_truncated FROM table
> we want
> ORDER BY 1 ASC, 2 DESC
> ORDER BY date_truncated
> Having just column number would cover both but having column alias would make
> queries more readable and human friendly. Plus make it one little stem closer
> to postgreSQL and SQL standard.
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