IS NULL

The IS NULL operator checks for NULL values.

Syntax

expr IS NULL
  1. expr can be any expression supported by the language.

Usage

The IS NULL operator can be used to test whether the left-hand expression is NULL.

This operator applies to most data types, except complex types like BYTE and TEXT.

Example

MAIN
  DEFINE n INTEGER
  LET n = NULL
  IF n IS NULL THEN
     DISPLAY "The variable is NULL."
  END IF
END MAIN