Posted by Erland Sommarskog on 08/13/07 21:58

Clive Swan (cliveswan@yahoo.co.uk) writes:
> I have a one-to-many relationship between [Ward].LA
> and [Property].BedroomNumber.
>
> For example
> [Property].BedroomNumber [Property].LA
> 1 00AA
> 5 00AA
> 10 00AA
> 15 00AA
> 20 00AA
> 10 00AA
> 25 00AA
>
> 1 00AB
> 1 00AB
> 2 00AB
> 1 00AB
> 20 00AB
> 10 00AB
> 25 00AB
>
> [Ward].LA
> 00AA
> 00AB
> 00AC
> 00AD
> 00AE
> 00AF
>
> [Ward] may have 10,000 records while [Property] might have
> 1 million records.
>
> I want to count and add up all the [Property].BedroomNumber with
> a unique [Property].LA, then add the result set to
> [Ward].BedroomNumber.
>
> So that I would have the following result:
>
> [Ward].LA [Ward].BedroomNumber
> 00AA 78
> 00AB 60
> 00AC 10
> 00AD 100
> 00AE 150
> 00AF 20

Maybe:

UPDATE Ward
SET BedroomNumber = P.cnt
FROM Ward W
JOIN (SELECT LA, COUNT(*) AS cnt
FROM Property
GROUP BY LA) P ON W.LA = P.LA

--
Erland Sommarskog, SQL Server MVP, esquel@sommarskog.se

Books Online for SQL Server 2005 at
http://www.microsoft.com/technet/prodtechnol/sql/2005/downloads/books.mspx
Books Online for SQL Server 2000 at
http://www.microsoft.com/sql/prodinfo/previousversions/books.mspx

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