Re: Howto get a group_number like row_number for groups

Hi,

dense_rank() over (order by object) % 2

> Hi
> I'd like to have an alternating colorindex in the output of a query that
> consecutive rows that are the same within a colum the same number.
> The query generates a readable output from a log-table and a few others
> that hold referenced texts.
> log (log_id int, log_event_fk int, object_fk int , ts timestamp)
> events (event_id int, event text)
> objects (object_id int, object text, is_active bool)
> the easy part :)
> mind the the ordering is not primarily based on the timestamp
> select log_id, event, object, ts
> from log
> join events on event_id = log_event_fk
> join objects on object_id = object_fk
> where object.is_active
> order by object, ts
> Now I'd need a dynamically generated column that alternates between 0
> and 1 so that I can later color the rows where object is the same.
> row_number() over (order by object, ts) % 2
> or rank() over (order by object, ts) % 2
> produces the 0/1 alternation for rows
> When I create a subselect for objects that adds the colorindex and join
> this to the log instead of objects, I get the group-color only if I
> omit the sorting on the timestamp.
> When I order the outer select by object, ts the colorindex gets 0 in
> every row. :(
> I'd like to get something as this
> 3, up, dev3, 2010-4-2 10:00, 0
> 8, down, dev3, 2010-4-2 14:00, 0
> 9, down, dev3, 2010-4-2 15:00, 0
> 1, up, dev7, 2010-4-2 09:00, 1
> 5, down, dev7, 2010-4-2 17:00, 1
> 2, up, dev11, 2010-4-2 12:00, 0
> 7, down, dev11, 2010-4-2 13:00, 0
> .
> .
> regards :)
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