Re: Record (entity) versions...
Date: Fri, 09 Jul 2004 21:58:39 -0700
Message-ID: <e5tue0phd2auv5gostdfmaa62b99ee2foh_at_4ax.com>
sztomi_at_seznam.cz (sz Tomi) wrote:
[snip]
>SELECT i.date,c.name,c.address FROM invoices AS i INNER JOIN customers
No, because you do not have enough information. You need to
associate a date range with the addresses and use that date range with
the customer id to select the then-current address. To my somewhat
less than expert eyes, this would involve creating a table of
addresses keyed to customer id and effective date.
>AS c ON i.CustomerId=c.CustomerId
>GO
>
>date name address
>
>2004-01-01 00:00:00.000 First Company Ltd. Boston
>2004-01-02 00:00:00.000 First Company Ltd. Boston
>2004-01-02 00:00:00.000 Second Company Ltd. Washington
>2004-01-03 00:00:00.000 Second Company Ltd. Boston
>
>Is it possible in any of the RDBMS's to make this last query return
>the following result set?
>
>2004-01-01 00:00:00.000 First Company Ltd. New York
>2004-01-02 00:00:00.000 First Company Ltd. New York
>2004-01-02 00:00:00.000 Second Company Ltd. Washington
>2004-01-03 00:00:00.000 First Company Ltd. Boston
To those more expert, am I on the right track?
Sincerely,
Gene Wirchenko
Computerese Irregular Verb Conjugation:
I have preferences.
You have biases.
He/She has prejudices.
Received on Sat Jul 10 2004 - 06:58:39 CEST