Updating a table field with a consecutive number

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От JORGE MALDONADO
Тема Updating a table field with a consecutive number
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Msg-id AANLkTinyLcB2aomrGoeDqZGsKzxEHRwsh+RQKSmCdT7j@mail.gmail.com
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Ответы Re: Updating a table field with a consecutive number  (Thomas Kellerer <spam_eater@gmx.net>)
Список pgsql-novice
Let's suppose I have a table like this one but without data in the Position field:
----------------------------------------------------------------
    Date                Score          Position
----------------------------------------------------------------
Jan. 2, 2011          1000               1
Jan. 2, 2011           999                2
Jan. 3, 2011          1000               1
Jan. 3, 2011           999                2
Jan. 3, 2011           998                3
Jan. 4, 2011          1000               1
Jan. 4, 2011           999                2
Jan. 4, 2011           998                3
Jan. 4, 2011           997                4
 
As you can see, the records are order by date and each date has a score and, depending on the score, a position is assign from 1 to n. I suppose I need to traverse the table ordered by date and score (one record at a time) and UPDATE the position field starting with 1 until the date changes. At this point, I would start from position 1 again until the next date change and so on. At least this is what I imagine I can do. I will appreciate any advice about a way of achieving my objective.
 
Respectfully,
Jorge Maldonado

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