Re: using min|max in where

Ben Carbery wrote:
> Hi, I have some sql like so:
>
> SELECT min(date) INTO d FROM interest_rate WHERE m_code = NEW.code;
> UPDATE interest_rate SET date = NEW.start_date, rate = NEW.initial_rate
> WHERE m_code = NEW.code AND date = d;
>
> Actually this is pgsql but I don't think that matters.
>
> I am wondering if I can make this more compact by somehow including the
> 'min' function in the WHERE clause, but WITHOUT simply moving the select in
> there. So not this..
>
> UPDATE interest_rate SET date = NEW.start_date, rate = NEW.initial_rate
> WHERE m_code = NEW.code AND date = (SELECT min(date) FROM interest_rate
> WHERE m_code = NEW.code);
>
> This is just an example but I seem to find this pattern a lot in my
> functions.

I think you want the HAVING clause of SELECT.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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