Re: Why is this a cross join?
От
Alban Hertroys
Тема
Re: Why is this a cross join?
Дата
Msg-id
D7456D20-E348-4EC2-994D-709EEAD2DB40@gmail.com
Ответ на
Why is this a cross join? (Tim Uckun)
Список
Дерево обсуждения
Why is this a cross join? Tim Uckun <timuckun@gmail.com>
Re: Why is this a cross join? Alban Hertroys <haramrae@gmail.com>
Re: Why is this a cross join? Tim Uckun <timuckun@gmail.com>
Re: Why is this a cross join? Tony Theodore <tony.theodore@gmail.com>
Re: Why is this a cross join? Tim Uckun <timuckun@gmail.com>
Re: Why is this a cross join? Kevin Grittner <kgrittn@ymail.com>
Re: Why is this a cross join? Tim Uckun <timuckun@gmail.com>
Re: Why is this a cross join? Kevin Grittner <kgrittn@ymail.com>
Re: Why is this a cross join? Adrian Klaver <adrian.klaver@gmail.com>
Re: Why is this a cross join? John R Pierce <pierce@hogranch.com>
Re: Why is this a cross join? Tony Theodore <tony.theodore@gmail.com>
On Feb 17, 2013, at 9:16, Tim Uckun wrote: > I have a seemingly simple query that returns way too many records. > Here is the count query >=20 > select count(*) from ( > select crm.* > from sap_crm_sales crm > inner join model_configurations mc on left(crm.customer_class, 6) > =3D left(mc.sap_code,6) > ) as s >=20 > The crm table has about 44K records, the model table has about 1K the > join produces about 9 million records Apparently the first 6 characters of those fields are quite common, = which gives you a result for every possible combination of the same = 6-character value. Alban Hertroys -- If you can't see the forest for the trees, cut the trees and you'll find there is no forest.
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