Re: avg() from multiple columns

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От Jason Tan
Тема Re: avg() from multiple columns
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Msg-id Pine.LNX.3.95.1010905122609.26091L-100000@rebel.rebel.net.au
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Ответ на avg() from multiple columns  (Miia Uski <miia.uski.155@student.lu.se>)
Ответы Re: avg() from multiple columns  ("Oliver Elphick" <olly@lfix.co.uk>)
Список pgsql-novice

If you want row by row averages try this:

select (col1+col2+col3)/3 from table;

If you wnat to average several columns over the whole table this seems to
work:

select avg(col1+col2+col3) from table;

Regards
Jason

On Sun, 2 Sep 2001, Miia Uski wrote:

> I have a question regarding taking the average value from several
> columns.
>
> I am trying to evaluate a survey with sql. I have one column per
> question, and one row per answered survey. The answers can have values 1
>
> - 4, unanswered questions have 0. I want to take the average from the
> answers of several questions that belong to the same category. For one
> question I can do like this:
>
> igv=> select avg("1.2") from igvdata
> igv-> where "1.2" > 0;
>
> How do I go about to have averages for several columns? Do I have to
> create views in order to avoid the "no answer"-values for each column?
>
>
> Thanks in advance,
>
> Miia
>
>
>
>
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--
------------------------------------------------------------------------------
Jason Tan                                                jason@rebel.net.au
     "Democracy is two wolves and a lamb voting on what to have for lunch.
                 Liberty is a well-armed lamb contesting the vote."
                               ~Benjamin Franklin, 1759
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