Function: IsNull
Description
Returns 1 if expression is null, otherwise returns 0 (zero).
Note: If you wish to determine whether a character field is empty, use the IsEmpty or IsBlank function.
Syntax
IsNull(expression)
Arguments
expression is a value, field or expression (number or date) to be evaluated.
Return value
This function returns 0 (zero) indicating that expression is not null or 1 (Boolean True) indicating that expression is null.
Calculated field example
This expression returns the value of the Average Price field if the value is valid. If the Average Price Field value is invalid, the expression returns a number that indicates this (i.e., 999999). If(IsNull([Average Price])=1,999999,[Average Price])
Filter/Find example
This expression removes records with Null values in the Average Price field: IsNull([Average Price])=0