NULL Expression

A conditional expression that tests for null values.

The expression has the following format:

operand [IS] NULL

The operand can be any of the following:

A numeric field, date field, or alphanumeric field defined as nullable in Working Data, Parameter Data, or a dataview definition.
An arithmetic expression, numeric function, or alphanumeric function with a nullable operand. For example:
```
IF STATE IS NULL
```
The expression is True if the operand evaluates to the null value. Otherwise, the expression is False.

You can also specify “operand is NOT NULL”. This expression is False if the operand evaluates to the null value. Otherwise, the expression is True.