Null-capable fields used by the INCREL parameter

The INCREL parameter allows a value of *NULL as input for a field value. You can use the *EQ and *NE operators with the *NULL value to test whether a field in a database file contains the null value or not.

*EQ means that the value is null, and *NE means that the value is not null when you specify the *NULL value. The *NULL value is not limited to null-capable fields.