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

Chapter 7: Adding More to Our Queries
These are just the highlights. The possibilities of different mixes and additional situations are positively
endless.
I can’t stress enough how important it is when in doubt — heck, even when you’re not
in doubt but performance is everything — to make reasonable tests of competing solutions
to a problem. Most of the time the blanket rules will be fine, but not always. By
performing reasonable tests, you can be certain you’ve made the right choice.
Summary
The query options you learned back in Chapters 3 and 4 cover perhaps 80 percent or more of the query
situations that you run into, but it’s that other 20 percent that can kill you. Sometimes the issue is whether
you can even find a query that will give you the answers you need. Sometimes it’s that you have a particular
query or sproc that has unacceptable performance. Whatever the case, you’ll run across plenty of
situations where simple queries and joins just won’t fit the bill. You need something more and, hopefully,
the options covered in this chapter have given you a little extra ammunition to deal with those tough
situations.
Exercises
1. Write a query that returns the hire dates of all AdventureWorks2008 employees in MM/DD/YY
format.
2. Write separate queries using a JOIN, a subquery, and then an EXISTS, to list all Adventure-
Works2008 persons who have not placed an order.
3. Show the most recent 5 orders that were purchased from account numbers that have spent more
than $70,000 with AdventureWorks.
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