Andreas <maps.on@xxxxxxx> writes:
> How would I group the table so that it shows groups that have
> similarity () > x ?
>
> Lets say the table looks like this:
>
> id, txt
> 1, aa1
> 2, bb1
> 3, cc1
> 4, bb2
> 5, bb3
> 6, aa2
> ...
>
> How would a select look like that shows:
>
> id, txt, group_id
> 1, aa1, 1,
> 6, aa2, 1,
> 2, bb1, 2,
> 4, bb2, 2,
> 5, bb3, 2,
> 3, cc1, 3
The following query will do that, but it's convoluted:
WITH grp (t1, id, t2) AS (
SELECT t1.txt, t1.id, t2.txt
FROM tbt t1
LEFT JOIN tbt t2 ON t2.txt > t1.txt
WHERE t2.txt IS NULL OR similarity(t1.txt, t2.txt) > 0
)
SELECT t1, min(id)
FROM (
SELECT t1, id
FROM grp
UNION ALL
SELECT t2, id
FROM grp
WHERE t2 IS NOT NULL
) dummy
GROUP BY t1
ORDER BY t1
--
Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-general
