.Nullstring Statement--Specify String for Null Value
The .nullstring statement specifies an alternate null string.
This statement has the following format:
.nullstring | .nullstr 'null_string' | expression
The parameters for the .nullstring statement are as follows:
null_string
Any string of characters. Enclose the string in single quotes, so Report-Writer can properly handle leading and trailing blanks, which are important in some format specifications.
expression
A string expression that evaluates to any character string. Precede all variables that are part of the expression with a dollar sign ($). For more information, see the chapter "Report-Writer Expressions and Formats."