The FROM clause identifies the class in which to search for instances that match the query string. Only non-joined expressions are supported, which means that a valid WQL FROM clause includes only a single class.
The FROM clause is represented by the abstract class, fromExp. Currently, NonJoinExp is the only direct subclass of fromExp. The NonJoinExp subclass represents FROM clauses with only one table (CIM class) to which the SELECT operation is applied.