[jira] [Comment Edited] (PHOENIX-1749) ORDER BY should support ordinal position as well as expression

["Alicia Ying Shu (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/PHOENIX-1749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14484060#comment-14484060 ] 

Alicia Ying Shu edited comment on PHOENIX-1749 at 4/7/15 9:18 PM:
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[~jamestaylor] A question. If using RowProjector for order by position, can we use projector.getColumnProjector(index-1).getExpression() directly to get the expression? If yes, why setting columnRef for Visitor. If no, do we need to use ParseNode.accept(visitor)?


was (Author: aliciashu):
[~jamestaylor] A question. If using RowProjector for order by position, can we use projector.getColumnProjector(index-1).getExpression() directly to get the expression? If yes, why setting columnRef for visitor. If no, then we need to use ParseNode.accept(visitor)?

> 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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