IS [NOT] [$]NULL

Checks a value to see if it is $Null.

Syntax

expression IS [NOT] $NULL

Parameters

expression

Any expression.

Return Value

Logical.

Comments

An IS $NULL comparison is logically true if expression is valueless (unassigned). If expression has been assigned any value (including the null string), then the comparison is logically false.

An IS NOT $NULL comparison is logically true if expression has been assigned any value (including the null string). If expression is valueless (unassigned), then the comparison is logically false.

$NULL can also be written as NULL.

Example

To find all employees whose records have no value recorded in the Age field, and then change that value to 39, enter

change all Employees where Age is $Null let Age = 39

 

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