Re: sql join question
От | Ragnar Hafstað |
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Тема | Re: sql join question |
Дата | |
Msg-id | 1109746357.16690.98.camel@localhost.localdomain обсуждение исходный текст |
Ответ на | Re: sql join question (Scott Frankel <leknarf@pacbell.net>) |
Ответы |
Re: sql join question
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Список | pgsql-general |
On Tue, 2005-03-01 at 16:51 -0800, Scott Frankel wrote: > Sweet! And not so sweet. > > The natural join worked beautifully with my test schema; but it failed > to yield any rows with my real-world schema. I think I've tracked down > why: duplicate column names. i.e.: > ... > CREATE TABLE palettes (palette_pkey SERIAL PRIMARY KEY, > palette_name text UNIQUE DEFAULT NULL, > qwe text); > > CREATE TABLE tones (tone_pkey SERIAL PRIMARY KEY, > tone_name text UNIQUE DEFAULT NULL, > palette_pkey integer REFERENCES palettes, > qwe text); > > Are the 'qwe' columns in both tables clobbering each other and > preventing the > join from succeeding? the docs really explain this better than I can, but a table1 NATURAL JOIN table2 is shorthand fo a table1 JOIN table2 USING (list_of_common_keys) so: select color_name from palettes join tones USING (palette_pkey) join colors USING (tone_pkey) where palette_name='plt1'; see: http://www.postgresql.org/docs/8.0/interactive/sql-select.html gnari
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