The Language of SQL- P46:Research has shown that, being pressed for time, most readers tend to skip the introduction of any book they happen to read and then proceed immediately to the first real chapter. With that fact firmly in mind, we will only cover relatively unimportant material in the introduction, such as an explanation of what you will and will not learn by reading this book. | Spreadsheets and Pivot Tables 211 However the pivot table also adds some key elements that greatly enhance its usefulness First a pivot table is completely interactive. Rather than viewing a static crosstab report the user can modify the pivot table quickly by rearranging data elements into the various areas rows columns and data. In addition pivot tables provide a fourth data area called the page which allows for data items to be used in filtering but not displayed. The data in pivot tables exists as a separate store of data and can even be saved as a separate file. Because the data in a pivot table exists on its own users can rearrange the data without affecting the data from which the pivot table was created. Pivot tables allow for additional data selection. For example specific values of various data items can be excluded. Or the aggregated values in the data area of the pivot table can be changed from sums to counts. Pivot tables can add drill-down functionality to the data. For example if the underlying data contains columns such as country state and city the pivot table can be set up so you can double-click on a country to see all states in that country and then double-click again to see all cities in each state. Pivot tables allow users to drill through from summarized data to the underlying details. Thus you have the ability to double-click on any individual value in the data area to see the individual rows that contributed to that number. It s beyond the scope of this book to explore pivot tables in any amount of detail. But an awareness of what you can accomplish with pivot tables can be very useful for the SQL developer. Figure shows an example of a pivot table that was created from the same data as listed earlier but with the addition of two new columns Date and Subcategory. The Subcategory column is a further breakdown of the product category. In this pivot table the date product category and subcategory were all put in the rows area. This .
