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

3 8 More Than One Apart
2 2 Ends With Less Than Three
2 8 Ends With Less Than Three
1 7 Ends With Less Than Three
1 0 Ends With Less Than Three
1 1 Ends With Less Than Three
0 2 Ends With Less Than Three
0 4 Ends With Less Than Three
(10 row(s) affected)
There are a few of things to pay particular attention to in how SQL Server evaluated things:
❑ Even when two conditions evaluate to TRUE, only the first condition is used. For example, the
second-to-last row meets both the first (the last digit is smaller than 3) and third (the last digit is
within 1 of the ProductID) conditions. For many languages, including Visual Basic, this kind of
statement always works this way. If you’re from the C world (or one of many similar languages),
however, you’ll need to remember this when you are coding; no “break” statement is required —
it always terminates after one condition is met.
❑ You can mix and match what fields you’re using in your condition expressions. In this case, we
used SalesOrderID, ProductID, and both together.
❑ You can perform pretty much any expression as long as, in the end, it evaluates to a Boolean result.
Let’s try this out with a slightly more complex example. In this example, we’re not going to do the mixand-match
thing — instead, we’ll stick with just the one column we’re looking at (we could change
columns being tested — but, most of the time, we won’t need to). Instead, we’re going to deal with a
more real-life scenario that I helped solve for a rather large e-commerce site.
The scenario is this: Marketing people really like nice clean prices. They hate it when you apply a 10 percent
markup over cost, and start putting out prices like $10.13, or $23.19. Instead, they like slick prices
that end in numbers like 49, 75, 95, or 99. In our scenario, we’re supposed to create a possible new price
list for analysis, and they want it to meet certain criteria.
If the new price ends with less than 50 cents (such as our previous $10.13 example), then marketing
would like the price to be bumped up to the same dollar amount but ending in 49 cents ($10.49 for our
example). Prices ending with 50 cents to 75 cents should be changed to end in 75 cents, and prices ending
with more than 75 cents should be changed to end with 95 cents. Let’s take a look at some examples
of what they want:
If the New Price Would Be Then It Should Become
$10.13 $10.49
$17.57 $17.75
$27.75 $27.75
$79.99 $79.95
Chapter 11: Writing Scripts and Batches
357