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List:       postgresql-sql
Subject:    [SQL] replace EXCEPT by JOIN
From:       T E Schmitz <mailreg () numerixtechnology ! de>
Date:       2007-04-12 18:32:10
Message-ID: 461E7B2A.6040507 () numerixtechnology ! de
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The following construct does what I need but is there a better way of 
expressing this?



select * from
(

SELECT DISTINCT
  section.section_pk
FROM ITEM
  LEFT JOIN product product ON Item.product_fk = product.product_pk
  LEFT JOIN section section ON product.section_fk = section.section_pk
WHERE item.export = 'f'

EXCEPT

SELECT DISTINCT
  section.section_pk
FROM ITEM
  LEFT JOIN product product ON Item.product_fk = product.product_pk
  LEFT JOIN section section ON product.section_fk = section.section_pk
WHERE item.export = 't'

) as X

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