Re: [libreoffice-users] Other SQL question as it affects Base

Mark Stanton wrote:
> Keys are intended for the internal workings of the database, they are not meant to be
> used like this.
>
> What you want is the WHERE clause, or occasionally the HAVING clause, matching or
> excluding rows based on their data.
>
> Keys are NOT data and should not be used as such.
>
> Regards Mark Stanton One small step for mankind...

     I have a table, Reading, that contains three fields: ID, Date, and Meter. Date is the
date the meter is read, and Meter is the meter reading.
     I want to know how much electricity (KWH used) I have used each month. The query 
below will provide that information:

SELECT "Ending"."Date", "Ending"."Meter" -"Beginning"."Meter" AS "KWH Used" FROM "Power". 
"Reading" AS "Beginning" LEFT JOIN "Power". "Reading" AS" Ending" ON "Ending"."ID" =1 + 
"Beginning"."ID"

     Perhaps you are right about keys being intended for the internal workings of the 
database. While I don't have an example of one key being the multiple of the other key, it 
is possible. It just might not have any practical applications.

--Dan

--
For unsubscribe instructions e-mail to: users+help@global.libreoffice.org
Problems? http://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/
Posting guidelines + more: http://wiki.documentfoundation.org/Netiquette
List archive: http://listarchives.libreoffice.org/global/users/
All messages sent to this list will be publicly archived and cannot be deleted