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

AVG
This one is for computing averages. Let’s try running the order quantity query we ran before, but now
we’ll modify it to return the average quantity per order, rather than the total for each order:
SELECT SalesOrderID, AVG(OrderQty)
FROM Sales.SalesOrderDetail
WHERE SalesOrderID IN (43660, 43670, 43672)
GROUP BY SalesOrderID;
Notice that our results changed substantially:
SalesOrderID
------------ -------------
43660 1
43670 1
43672 3
(3 row(s) affected)
You can check the math — on order number 43672 there were 3 line items totaling 9 altogether (9 / 3 = 3).
MIN/MAX
Bet you can guess these two. Yes, these grab the minimum and maximum amounts for each grouping for
a selected column. Again, let’s use that same query modified for the MIN function:
SELECT SalesOrderID, MIN(OrderQty)
FROM Sales.SalesOrderDetail
WHERE SalesOrderID IN (43660, 43670, 43672)
GROUP BY SalesOrderID;
Which gives the following results:
SalesOrderID
------------ -----------
43660 1
43670 1
43672 1
(3 row(s) affected)
Modify it one more time for the MAX function:
SELECT SalesOrderID, MAX(OrderQty)
FROM Sales.SalesOrderDetail
WHERE SalesOrderID IN (43660, 43670, 43672)
GROUP BY SalesOrderID;
Chapter 3: The Foundation Statements of T-SQL
57