Coalesce()
Returns the first non NIL/NULL expression among its arguments.
Coalesce( <Expression,...> ) --> <Expression>
CoalesceEmpty()
Returns the first non empty expression among its arguments.
CoalesceEmpty( <Expression,...> ) --> <Expression>
DbSetNullValue()
Toggles NULL/NIL value support of a work area
DbSetNullValue([<lNullAllowed>]) -> lNullAllowed