BOOLEAN data type
The BOOLEAN data type is a 1-byte data type. The legal values for Boolean are true ('t'), false ('f'), or NULL. The values are not case sensitive.
You can compare a BOOLEAN column against another BOOLEAN column
or against Boolean values. For example, you might use these SELECT
statements:
SELECT * FROM sometable WHERE bool_col = 't';
SELECT * FROM sometable WHERE bool_col IS NULL;