SQL Boolean Value
A SQL Boolean is the result of a comparison operator. In the simple case, where NULL isn’t considered, a Boolean is either TRUE or FALSE.
When defining columns, you don’t define a SQL Boolean type, rather you use the BIT type, which stores Boolean values as 1, 0, or NULL for TRUE, FALSE, and NULL respectively.
TRUE and False values
The result of a comparison operator is a Boolean value, it is either True or False. For instance the statement 2 > 3 is FALSE; whereas 3 > 2 is TRUE.
To learn more about the SQL NOT Operator, check out these useful resources: