When using computed fields to determine elapsed differences between dates or times or datetime combination fields, the resulting computed field is automatically assigned an ELAPSED data type.
The ELAPSED data type cannot be manually assigned via the Data Definition Wizard or via the Define Field command but automatically appears in the table layout for the saved computed field. It can be seen by issuing a DISPLAY command on the command line in the Command Log.
When calculating elapsed differences between two datetime fields or values, the resulting elapsed difference may be just a number of days, a time, or both, as appropriate.
For full details on creating and specifying elapsed times, see Date, Time and Elapsed Time Constants (Literals).