SQL Server 2005 added the
PIVOT clause to T-SQL. A typical analytical use of the
PIVOT command is to convert temporal data into categorized data to make the data easier to view and analyze.
The first, and simplest, option for returning the temporal data is to query the data, grouping the fact information in such a way that it answers the questions being asked. For example, Listing 43.54 retrieves data from the
titles tables and provides the total number of business books sold, by year. Note that it’s difficult to see trends of the number of titles sold between years. It is also even more difficult to answer questions about how sales of one title compared to sales of other titles in the same year.