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help / color / mirror / Atom feedFrom: Tom Lane <tgl@sss.pgh.pa.us>
To: Seb <spluque@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: creating a new aggregate function
Date: Mon, 03 Mar 2014 19:17:55 -0500
Message-ID: <20952.1393892275@sss.pgh.pa.us> (raw)
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Seb <spluque@gmail.com> writes:
> Thanks for that suggestion. It seemed as if array_agg would allow me to
> define a new aggregate for avg as follows:
> CREATE AGGREGATE avg (angle_vector)
> (
> sfunc=array_agg,
> stype=anyarray,
> finalfunc=angle_vector_avg
> );
That's not going to work, for exactly this reason:
> ERROR: cannot determine transition data type
> DETAIL: An aggregate using a polymorphic transition type must have at least one polymorphic argument.
I see no reason to use a polymorphic type here anyway ... why not just
declare the transition data type as angle_vector[] ?
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, spluque@gmail.com
Subject: Re: creating a new aggregate function
In-Reply-To: <20952.1393892275@sss.pgh.pa.us>
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