Re: Selecting tree data
От | Pat Maddox |
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Тема | Re: Selecting tree data |
Дата | |
Msg-id | 810a540e0710261107i65292263q51934fbad70f46ed@mail.gmail.com обсуждение исходный текст |
Ответ на | Re: Selecting tree data (Michael Glaesemann <grzm@seespotcode.net>) |
Ответы |
Re: Selecting tree data
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Список | pgsql-general |
On 10/26/07, Michael Glaesemann <grzm@seespotcode.net> wrote: > > On Oct 26, 2007, at 10:56 , Pat Maddox wrote: > > > A bunch of options so far...but there's really no way to do this with > > standard SQL? > > What do you mean by "standard SQL"? Trees aren't inherently relational. Right now my table looks like this: posts id body parent_id root_id created_at so if I've got the records (1, 'post 1', NULL, 1, '4pm') (2, 'post 2', NULL, 2, '8pm') (3, 'post 3', 1, 1, '6pm') (4, 'post 4', 1, 1, '5pm') (5, 'post 5', 4, 1, '6pm') (6, 'post 6', NULL, 1, '5pm') I'd like to do a select and get them all in this order: (1, 'post 1', NULL, 1, '4pm') (4, 'post 4', 1, 1, '5pm') (5, 'post 5', 4, 1, '6pm') (3, 'post 3', 1, 1, '6pm') (6, 'post 6', NULL, 1, '5pm') (2, 'post 2', NULL, 2, '8pm') And reverse sorted would be: (2, 'post 2', NULL, 2, '8pm') (6, 'post 6', NULL, 1, '5pm') (1, 'post 1', NULL, 1, '4pm') (3, 'post 3', 1, 1, '6pm') (4, 'post 4', 1, 1, '5pm') (5, 'post 5', 4, 1, '6pm') Does that make sense? Pat
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