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

Chapter 7: Adding More to Our Queries
208
SELECT soh.OrderDate, sod.ProductID, SUM(sod.OrderQty) AS QtySold
FROM Sales.SalesOrderHeader soh
JOIN Sales.SalesOrderDetail sod
ON soh.SalesOrderID = sod.SalesOrderID
WHERE soh.OrderDate >= ‘2003-08-01’ AND soh.OrderDate < ‘2003-08-02’
GROUP BY soh.OrderDate, sod.ProductID
) AS s
ON (s.ProductID = smr.ProductID)
WHEN MATCHED THEN
UPDATE SET smr.QtySold = smr.QtySold + s.QtySold
WHEN NOT MATCHED THEN
INSERT (Year, Month, ProductID, QtySold)
VALUES (DATEPART(yy, s.OrderDate),
DATEPART(m, s.OrderDate),
s.ProductID,
s.QtySold);
Note that the semicolon is required at the end of the MERGE statement. While the semicolon remains
optional on most SQL Statements for backward-compatibility reasons, you’ll find it working its way into
more and more statements as a required delimiter of the end of the statement. This is particularly true
for multipart statements such as MERGE.
When you run this, you should get 192 rows affected, assuming you haven’t been altering the data in
AdventureWorks2008. Now, since our Sales.MonthlyRollup table was empty, there wouldn’t have been
any matches, so all rows were inserted. We can verify that by querying our Sales.MonthlyRollup table:
SELECT *
FROM Sales.MonthlyRollup;
This gets us back the expected 192 rows:
Year Month ProductID QtySold
------ ----- ----------- -----------
2003 8 707 242
2003 8 708 281
2003 8 711 302
…
…
2003 8 997 43
2003 8 998 138
2003 8 999 103
(192 row(s) affected)
Every row that was in the basic SELECT that powered our MERGE wound up being inserted into our
table. Let’s move on, however, to the second day of the month:
MERGE Sales.MonthlyRollup AS smr
USING
(
SELECT soh.OrderDate, sod.ProductID, SUM(sod.OrderQty) AS QtySold
FROM Sales.SalesOrderHeader soh
JOIN Sales.SalesOrderDetail sod
ON soh.SalesOrderID = sod.SalesOrderID
WHERE soh.OrderDate >= ‘2003-08-02’ AND soh.OrderDate < ‘2003-08-03’