They forgot "IS NOT DISTINCT FROM", which is, IMHO, the best god damn
operator ever invented. It works like "=", but adequately responds to
NULL:
postgres=# SELECT 1 IS NOT DISTINCT FROM 1;
?column?
----------
t
(1 row)
postgres=# SELECT NULL IS NOT DISTINCT FROM NULL;
?column?
----------
t
(1 row)
Oh my god. We had a bug awhile back due to null equality comparison treating nulls as non-equal; I wish I'd known about mysql's equivalent ("<=>") back then!
Actually this blog is not about how many ways you can use NULL in the database. It's all about the people who have programming experience (C/C++/JAVA) and try to write the SQL queries.
...I think you are misunderstanding the whole reason for the IS NOT DISTINCT FROM operator, which is exactly that.
"SELECT NULL = NULL" will return NULL, use that if you want the standard way. There are many cases where you want it to return true though, and the boilerplate for that sucks, so IS NOT DISTINCT FROM has a very useful place in the dialect.
