Re: functions/operators with 2 sets as arguments

Tom Lane wrote:
> Jochem van Dieten <jochemd@oli.tudelft.nl> writes:
>>
>> While trying to create an operator to test if 2 intervals
>> overlap, I ran into the following limitation:
>>
>> ERROR:  Functions and operators can take only one set argument
>> (PostgreSQL 7.3.2 on OpenBSD)

> It's still there, and is unlikely to go away (I think future development
> is more likely to go in the direction of deprecating/removing set-valued
> functions in SELECT expressions than extending the facility).
>
> Why would interval overlap testing require such a function?  What are
> you trying to do, exactly?
>
> Also, have you looked at the SQL OVERLAPS operator? Your problem might
> be solved already, if what you are after corresponds to what the SQL
> authors thought would be useful ...

The SQL OVERLAPS predicate is almost what I want, but I would
like to have an operator that returns TRUE if the end of the
first interval is the beginning of the second interval. But since
2 sets can't be used, I will fix it by simply adding an extra
condition to the query.

Jochem

--
When you don't want to be surprised by the revolution
organize one yourself
     - Loesje