Re: big distinct clause vs. group by

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Vitalii,

this sounds promising, can you send me that?

Best Regards,
Uwe


2011/4/25 Віталій Тимчишин <tivv00@xxxxxxxxx>


2011/4/23 Robert Haas <robertmhaas@xxxxxxxxx>
On Apr 18, 2011, at 1:13 PM, Uwe Bartels <uwe.bartels@xxxxxxxxx> wrote:
> Hi Robert,
>
> thanks for your answer.
> the aggregate function I was talking about is the function I need to use for the non-group by columns like min() in my example.
> There are of course several function to choose from, and I wanted to know which causes as less as possible resources.

Oh, I see. min() is probably as good as anything. You could also create a custom aggregate that just always returns its first input. I've occasionally wished we had such a thing as a built-in.


I've once done "single" grouping function - it checks that all it's input values are equal (non-null ones) and returns the value or raises an error if there are two different values. 

Best regards, Vitalii Tymchyshyn 



--
Best regards,
 Vitalii Tymchyshyn


[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux