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Posted by Matt on 07/01/07 20:31
On Jul 1, 7:47 pm, gordonb.fs...@burditt.org (Gordon Burditt) wrote:
> >Constructed a fairly big table with 20 rows, most of which are
> >TINYINTs based on user selection for a dropdown box. This is the form:
>
> >http://www.threechords.org/spb/survey/
>
> >Each field obviously corresponds to a row in the table, and the
> >majority are integers indicating the user's selection.
>
> This doesn't really have that much to do with PHP; it's more related to
> SQL and databases in general.
>
> >My issue is how to do meaningful stuff with the stored data. I believe
> >I need to use GROUP BY functionality but I'm not certain - how can I
> >calculate, say, the number of "1" ('Excellent') values for the field
> >"writing_quality"?
>
> select count(*) from survey where writing_quality=1;
>
> If you want the whole distribution of votes:
>
> select writing_quality, count(writing_quality) from survey group by writing_quality;
>
> which will get you a list of writing_quality values and the number
> of votes that gave that value, e.g.:
>
> writing_quality count(writing_quality)
> 1 32
> 2 86
> 3 74
> 4 50
> 5 22
> 7 1
>
> (note: it seems nobody voted "6", so it is not listed).
>
> If you want an overall average:
>
> select avg(writing_quality) from survey;
>
> which might give you 2.8 as an average.
>
> You can also try things like:
>
> select avg(writing_quality) from survey where sex = 'Male' and age >= 20 and age < 30;
>
> which gives you a score from a specific segment of your users.
Thank you very much, I've managed to construct a nice-looking page
(http://www.threechords.org/spb/survey/results.php) - apologies for my
poor group choice here.
Matt
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