Why can't NULL be converted to JSON's null in postgreSQL?

Question

I can perform

SELECT to_json(1)
SELECT to_json(1.4)
SELECT to_json(\'this is a nice json text\')
SELECT to_json(\'{\"become\":\"json\"}\')
SELECT to_json(\'n         


        

Answer 1

Pavel Stehule's answer is great, and has led me to a simpler solution:

SELECT 'null'::json;