Re: adding operators - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: adding operators
Date
Msg-id 470137BD.20104@dunslane.net
Whole thread Raw
In response to Re: adding operators  ("Islam Hegazy" <islheg@gmail.com>)
List pgsql-hackers

Islam Hegazy wrote:
> Thanks for this information. It was really helpful.
>
> Another problem that is facing me is altering existing functions. For 
> example, what if I want to change the execution of the SUM function to 
> work as follows:
>
> select sum(a)
> from mytable w(5);
>
> which means to sum only 5 records or records that arrived in the last 
> 5 minutes. Do I need to change the core code of PostgreSQL to 
> implement such thing?
>
>

The first can be done with a limit clause, the second using a where 
clause on a timestamp column - there is no good case that I can see for 
either usage, not to mention the question of standards compatibility.

cheers

andrew


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