Performing Calculations and Using Functions
Cristian Darie, Karli Watson, Chris Hart, Kevin J. Hoffman, Julian Skinner · Apress eBooks · 2003
A number of times over the past few chapters you found that selecting data based on the simple column name didn’t meet your needs. Instead you needed to combine values or calculate new values based on the data in your database, such that the values you obtained in your results were ready for you to use. You have, for example, concatenated strings to create columns more suited to applications, and you’ve also performed simple calculations involving numerical data, such as multiplying the values of two columns together.