Re: Function to Pivot data
От | Bruno Wolff III |
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Тема | Re: Function to Pivot data |
Дата | |
Msg-id | 20020212172604.GA15113@wolff.to обсуждение исходный текст |
Ответ на | Re: Function to Pivot data (Andrew Sullivan <andrew@libertyrms.info>) |
Список | pgsql-general |
On Tue, Feb 12, 2002 at 11:49:26AM -0500, Andrew Sullivan <andrew@libertyrms.info> wrote: > On Mon, Feb 11, 2002 at 07:39:38AM -0600, Bruno Wolff III wrote: > > > The way I did this for a tiny book database I have set up for my wife > > to keep track of books is to have an edition table, an author table and > > a table of edition author pairs. It isn't ordered, but it could be > > by adding another field to the edition, author pairs. > > That was my original suggestion. But then, how do you make sure that > every edition has only one first author, only one second, &c.? Also, > you can't have a generic query which gets the authors for every book, > and shows them in the tabular output that was originally desired > (hence the pivot table). You could, however, write some code outside > the database which would first query the book_author table, figure > out how many authors were necessary, and then build the real query > that way. I did have another suggestion in there about using a third column on the author - book records to use for ordering. If you use something like that you could write general queries using order by to get things in author order.
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