Re: get first and last row in one sql as two columns

The window function works for me (with adding  limit 1 in the end to output only one row

 needed instead of many duplicate rows).

thanks very much. 

On Thu, Sep 3, 2015 at 6:51 AM, Dickson S. Guedes <listas@guedesoft.net> wrote:

On Wed, Sep 02, 2015 at 07:14:40PM -0400, Tom Smith wrote:
> Hi:
>
> I need to get the first and last tow in one sql like below
>
> select first(col1), last(col1) from table order by col1

Have you tried the window functions [1] last_value and first_value?

You could use something like:

SELECT first_value(col1) over (order by col1),
       last_value(col1)  over (order by col1)
FROM table;

It should be as simple as that, or I miss your point.


[1] http://www.postgresql.org/docs/current/static/functions-window.html


[]s
--
Dickson S. Guedes
@guediz - http://github.com/guedes