A database excels at keeping track of things—itsy bitsy teeny tiny details about hundreds, thousands, even millions of little things. But people aren't so good at dealing with all that detail (hence the invention of the database). They like to see the big picture. If you want to understand your customer's music tastes, a report of 200,000 individual CD sales won't do you much good: The information is in there somewhere, but your feeble mind stands no chance of ferreting it out. But a report that divides that information into 25 music genres, each with sales totals, both in aggregate and by gender, helps you interpret all those reams of data at a glance. In other words, a well-designed report summarizes the data for you. FileMaker's not only fantastic at showing you information, it also excels at helping you see what it all means.
In Chapter 5, you learned how to create reports that show lists of records, but they don't include any so-called summary data. They show only the details. To get summary information, you need summary fields.
In Chapter 3, you learned that a summary field isn't associated with records like the other field types (see Timestamp). Instead, summary fields gather up and process data from several records. Creating summary fields is much easier than describing what they do, as you can see from the following example.
In the People database, choose File → Manage → Database.
You're about to add a field that counts the people in ...