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Re: count (DISTINCT field) OVER ()

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On Nov 9, 2011, at 18:52, Tarlika Elisabeth Schmitz <postgresql6@xxxxxxxxxxxxxxxxxxxx> wrote:

> I would like to implement the equivalent of "count (DISTINCT field) OVER
> ()":
> 
> 
> SELECT 
>  id, name, similarity(name, 'Tooneyvara') as delta, 
>  count (id) OVER() AS cnt
>  FROM vtown
>  WHERE
>      similarity(name, 'Tooneyvara') > 0.1
>  ORDER BY  delta DESC
> 
> produces result:
> 1787    Toomyvara    0.5    4
> 1787    Toomevara    0.4    4
> 1700    Ardcroney    0.105    4
> 1788    Townsfield    0.1    4
> 
> What I would like is a "3" in the cnt column (ignoring id duplicates).
> 
> 
> How can I achieve this?
> 
> 
> The best I can come up with is:
> 
> SELECT id, name,delta,  count (*) OVER() 
> FROM (
> SELECT DISTINCT ON (id)
>  id, name, similarity(name, 'Tooneyvara') as delta 
>  FROM vtown
>  WHERE
>    similarity(name, 'Tooneyvara') > 0.1
>    ORDER BY id, delta DESC
> ) AS x
> ORDER by delta DESC 
> 
> -- 
> 
> Best Regards,
> Tarlika Elisabeth Schmitz
> 
> -- 
> Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
> To make changes to your subscription:
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1.  Write your main query in a WITH (CTE)
2.  Query #1 with appropriate GROUP BY clause (CTE)
3.  In the main statement JOIN 1 and 2

David J.


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