SQL NULL is also coerced to different boolean values depending on context e.g. in a WHERE clause NULL is coerced to false, whereas in a CHECK constraint NULL is

SQL NULL is also coerced to different boolean values depending on context e.g. in a WHERE clause NULL is coerced to false, whereas in a CHECK constraint NULL is coerced to true https://dbfiddle.uk/C5JqMP8O https://dbfiddle.uk/C5JqMP8O