COALESCEC accepts one
or more character expressions. The COALESCEC function checks the value
of each expression in the order in which they are listed and returns
the first non-null or nonmissing value. If only one value is listed,
then the COALESCEC function returns the value of that expression.
If all the values of all expressions are null or missing, then the
COALESCEC function returns a null or missing value depending on whether
you are in ANSI mode or SAS mode.
For more information,
see How FedSQL Processes Nulls and SAS Missing Values.