Re: Help with CREATE FUNCTION

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От David G. Johnston
Тема Re: Help with CREATE FUNCTION
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Msg-id CAKFQuwatpyHOpBDssmEuAx21Q37wJkMXyxvFFC6KvcUMpGzpMA@mail.gmail.com
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Ответ на Re: Help with CREATE FUNCTION  (Sándor Daku <daku.sandor@gmail.com>)
Ответы Re: Help with CREATE FUNCTION  (Kip Warner <kip@thevertigo.com>)
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On Mon, Apr 18, 2016 at 3:02 AM, Sándor Daku <daku.sandor@gmail.com> wrote:

On 18 April 2016 at 08:22, Kip Warner <kip@thevertigo.com> wrote:
Hey list,

I am having difficulty using CREATE FUNCTION with a subordinate SELECT
query that should operate on exactly two rows.

    http://pastebin.com/7b3Vxbuh

Any help is appreciated.
Your select should look like this:

select your_const*abs(ta.col1-tb.col1)+... 
from my_table as ta, my_table as tb where ta.id = arg_id_a and tb.id = arg_id_b;

This kind of unqualified join is usually stupid, but in this time exactly what you need.    


​Arguably its still stupid :)

SELECT [...]
FROM (SELECT * FROM my_table WHERE id = arg_id_a) AS ta
CROSS JOIN (SELECT * FROM my_table WHERE id = arg_id_b​) AS tb

David J.

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