Mode Description
RAW RAW mode transforms each row in the query result set into an XML element with the generic identifier row. RAW maps each non-null column value to an attribute of the XML element in which the attribute name is the same as the column name.
AUTO AUTO mode returns query results in a simple, nested XML tree. AUTO represents each table in the FROM clause, from which the SELECT clause lists at least one column, as an XML element. AUTO maps the columns in the SELECT clause to the appropriate element's attributes. See SQL Server Books Online (BOL) for a full discussion of the effect tables and ordering of the SQL statement have on the returned XML.
EXPLICIT With AUTO mode, the database returns query results in a simple, nested XML tree, giving you limited control over the tree's shape. With EXPLICIT mode, you can specify the shape of the XML tree. However, you must write queries in a specific way so that you explicitly define the additional information about your desired nesting.