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Re: Should Aggregate Functions always return one row? - Mailing list pgsql-bugs

From Tom Lane
Subject Re: Should Aggregate Functions always return one row?
Date
Msg-id 16437.1074998751@sss.pgh.pa.us
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In response to Should Aggregate Functions always return one row?  (wilhelm.pakulla@gmx.de)
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wilhelm.pakulla@gmx.de writes:
> So, if I use the max() aggregate, I receive one row with the value NULL. Is
> that correct?

Yup, that's what the SQL spec says to do, and it seems reasonable to me.

IIRC, the spec also says that SUM() over no rows returns NULL, which is
less reasonable --- I'd have defined it as returning zero, myself.
But when in doubt we follow the spec.

            regards, tom lane

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