Knowing how to use expressions is arguably one of the most important concepts you’ll learn in this book. You’ll use expressions for a variety of purposes when working with SQL. For example, you would use an expression to
Create a calculated column in a query
Search for a specific column value
Filter the rows in a result set
Connect two tables in a JOIN operation
We’ll show you how to do this (and more) as we work through the rest of the book. We begin by showing you how to use basic expressions in a SELECT clause.
Throughout this chapter, we use the “Request/Translation/Clean Up/SQL” technique introduced in Chapter 4.
You can use basic expressions in a SELECT clause to clarify information in a result set ...