Why isn't zero date when compared to null, null?

Question

1. SELECT NULL; prints

   <null>

2. SELECT CAST('0000-00-00' AS DATE); prints

   <null>

3. SELECT NULL IS NULL; prints

   1

4. SELECT CAST('0000-00-00' AS DATE) IS NULL; prints

   0

Why isn't the result of the 4th statement 1?

Tested using DataGrip while connecting to MySQL 5.7.17 on windows.

Answer 1

Because the 2. isn't true:

SELECT CAST('0000-00-00' AS DATE); prints

0000-00-00

It doesn't print

NULL

Answer 2

4th statement show the result 0000-00-00

In mysql Only null is null. Everything else is not, so that it returns 1