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From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-1749) ORDER BY should support column position as well as column alias
Date Fri, 27 Mar 2015 20:20:53 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-1749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14384546#comment-14384546
] 

James Taylor commented on PHOENIX-1749:
---------------------------------------

[~julianhyde] - somewhat esoteric SQL question. Is it allowed to use a bind variable for the
ordinal position of an ORDER BY:
{code}
SELECT a, b, TRUNC(current_date(),'HOUR') AS date_truncated FROM table 
ORDER BY ? ASC, ? DESC
{code}
where I'd bind the column ordinal position?

What about this, where it's an expression that evaluates to a constant?
{code}
SELECT a, b, TRUNC(current_date(),'HOUR') AS date_truncated FROM table 
ORDER BY 2*2-3
{code}
Weird, I know, but what should happen?


> ORDER BY should support column position as well as column alias
> ---------------------------------------------------------------
>
>                 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.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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