NULL predicate

The NULL predicate tests for null values.

Read syntax diagramSkip visual syntax diagram
>>-expression--IS--+-----+--NULL-------------------------------><
                   '-NOT-'         

The result of a NULL predicate cannot be unknown. If the value of the expression is null, the result is true. If the value is not null, the result is false.

If NOT is specified, the result is reversed.

Examples

   EMPLOYEE.PHONE IS NULL
 
   SALARY IS NOT NULL