Re: Outer join statement ?
От | Alexandru COSTIN |
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Тема | Re: Outer join statement ? |
Дата | |
Msg-id | Winr5.19$bo5.752@nreader1.kpnqwest.net обсуждение исходный текст |
Список | pgsql-sql |
Hello, There are 2 ways of doing outer joins, both are relatively expensive from the CPU time point of view 1. Create a function that returns the ojined value, or null if the value does not exists in the secod table 2. Use a union beetwen a left join and a straight select with a where condition. Next there's an example inspired from the Adison Westley book (I suggest you grab a copy from the postgresql site. (/docs) select customer.name,salesorder.order_id from customer join salesorder on customer.cust_id=salesorder.fk_cust_id union all select customer.name,null::int4 from customer where customer.cust_id not in (select fk_cust_id from salesorder); Probably an improvement here is to use exists on the second select, but I didn't have the time to document. Anyway, this will not work embedded in a view ("union all" is not supported in views). Alexander "Nasdaq" <fb@techbourse.com> wrote in message news:fb-3008002344340001@du-211-67.lyon.dialup.freesurf.fr... > The statement "Outer Join" is not available in Postgres ? > Is there an extension provided by a third company that implement this > functionnality ? > > If not do you know when this functionnality will be available in > Postgres ? > > Thank > > Fred > > -- > TechBourse : le premier site en FRANCAIS d�di� le NASDAQ > http://www.techbourse.com
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