is null operator
Applies to: 
Databricks SQL Databricks Runtime
Tests whether expr is NULL.
Syntax
expr is [not] null
Arguments
expr: An expression of any type.
Returns
A BOOLEAN.
If not is specified this operator is a synonym for isnotnull(expr).
Otherwise the operator is a synonym for isnull(expr).
If expr is a VARIANT result of a:
- JSON path expression with a valid path,
- parse_json function,
- variant_explode table-valued function, or
- variant_explode_outer table-valued function
the result of is null is always false.
Use the is_variant_null function function to check if the VARIANT encoded value is NULL, or cast the VARIANT to a specific type and check if the result is NULL.
Examples
> SELECT 1 is null;
false
> SELECT 1 is not null;
true