MySQL allows BOOLEAN as an alias for BIT:
CREATE TABLE foo (
But if you then use
both fields will show up as BIT(1).
It also allows the keywords TRUE and FALSE:
UPDATE foo SET flag = True WHERE id = 777;
But, again, if you then do
SELECT flag FROM foo
you will see a 1 or 0 value for the BIT field.
So they really just have 3 aliases in place: BOOLEAN for BIT(1), TRUE for 1, FALSE for 0.