ASA Database Administration Guide
  Database Options
    Alphabetical list of options

OUTPUT_NULLS option [ISQL]

Function 

Controls the way NULL values appear in result sets.

Allowed values 

String

Default 

'NULL'

Description 

This option controls the way NULL values appear in result sets. Every time a NULL value is found in the result set, the string from this option is returned instead. This setting applies to data displayed in Interactive SQL on the Results tab in the Results pane as well as to data in output files generated by the OUTPUT statement. This option affects only ASCII, HTML, and SQL output formats.