Re: Order by optimisations?

On K, 2005-07-13 at 16:08 +0800, Christopher Kings-Lynne wrote:
> Hi,
> 
> Does PostgreSQL do the following optimisation:
> 
> SELECT * FROM diary WHERE date = '2005-05-01' ORDER BY date;
> 
> or in fact even better (for my situation)
> 
> SELECT * FROM diary WHERE date BETWEEN '2005-05-01' AND '2005-05-01' 
> ORDER BY date;
> 
> Does it know that the input to the sort routine is already sorted and 
> hence is a no-op?

Yes

try EXPLAIN ;)

-- 
Hannu Krosing <hannu@skype.net>