Is Null Comparison
The is null predicate has the following syntax:
is [not] null
The is null predicate explicitly tests for a null value. A null is not greater than or less than anything and is not equal to anything, even another null value. For example, the predicate
where column1=column2
does not evaluate to "true" even if both columns are null. To explicitly test a column for a null value, you must use the is null predicate. Similarly, an explicit test can be made for the absence of a null value by specifying the is not null predicate:
column1 is not null
Last modified date: 08/28/2024