Dynamic Demographics tables are provided in two forms – pivoted and unpivoted. The two table types are distinguished by the letters p (pivoted) and u (unpivoted) in their file names.
Pivoted tables provide all variables for a particular geography in a single, unique table row. When mapped, a pivoted table yields a single polygon for the geography that contains all attributes.
Unpivoted tables provide variables split across multiple rows, reducing the number of columns but, consequently, increasing the number of rows, as each row represents a unique set of variables for a particular geography. Unpivoted tables are useful for querying against one or more categories of data. When mapped, unpivoted tables yield multiple polygons for each geography.