Beginning Microsoft SQL Server 2008 ... - S3 Tech Training

So let’s take this now and apply it to our requirements. Again, what we want are the account numbers
and territories of all the companies that have ordered both HL Mountain Rear Wheel and HL Mountain
Front Wheel. So our query should look something like this:
SELECT DISTINCT sc.AccountNumber, sst.Name
FROM Sales.Customer AS sc
JOIN Sales.SalesTerritory sst
ON sc.TerritoryID = sst.TerritoryID
JOIN
(SELECT CustomerID
FROM Sales.SalesOrderHeader soh
JOIN Sales.SalesOrderDetail sod
ON soh.SalesOrderID = sod.SalesOrderID
JOIN Production.Product pp
ON sod.ProductID = pp.ProductID
WHERE pp.Name = ‘HL Mountain Rear Wheel’) AS dt1
ON sc.CustomerID = dt1.CustomerID
JOIN
(SELECT CustomerID
FROM Sales.SalesOrderHeader soh
JOIN Sales.SalesOrderDetail sod
ON soh.SalesOrderID = sod.SalesOrderID
JOIN Production.Product pp
ON sod.ProductID = pp.ProductID
WHERE Name = ‘HL Mountain Front Wheel’) AS dt2
ON sc.CustomerID = dt2.CustomerID;
We wind up with 58 accounts:
AccountNumber Name
------------- ----------------------------
AW00029484 Southeast
AW00029490 Northwest
AW00029499 Canada
…
…
AW00030108 Canada
AW00030113 United Kingdom
AW00030118 Central
(58 row(s) affected)
Chapter 7: Adding More to Our Queries
If you want to check things out on this, just run the queries for the two derived tables separately and
compare the results.
For this particular query, I needed to use the DISTINCT keyword. If I didn’t, then I would have potentially
received multiple rows for each customer — for example, AW00029771 has ordered the HL Mountain
Rear Wheel twice, so I would have gotten one record for each. I only asked which customers had ordered
both, not how many had they ordered.
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