is false operator
Applies to: 
Databricks SQL Databricks Runtime
Tests whether expr is false.
Syntax
expr is [not] false
Arguments
expr: A BOOLEAN or STRING expression.
Returns
A BOOLEAN.
If expr is a STRING of case-insensitive value 't', 'true', 'y', 'yes', or '1' it is interpreted as a BOOLEAN true.
If the values is 'f', 'false', 'n', 'no', or '0' it is interpreted as a BOOLEAN false.
If expr is NULL the result is false.
If not is specified this operator returns true if expr is false or NULL and false otherwise.
If not is not specified the operator returns true if expr is true and false otherwise.
Examples
SQL
> SELECT true is false;
false
> SELECT 'f' is false;
true
> SELECT false is false;
true
> SELECT NULL is false;
false
> SELECT 'invalid' is false;
Error: CAST_INVALID_INPUT
> SELECT false is not false;
false
> SELECT 'f' is not false;
false
> SELECT true is not false;
true
> SELECT NULL is not false;
true