Why does NULL = NULL evaluate to false in SQL server

Question

In SQL server if you have nullParam=NULL in a where clause, it always evaluates to false. This is counterintuitive and has caused me many errors. I do understa

Answer 1

If you are looking for an expression returning true for two NULLs you can use:

SELECT 1 
WHERE EXISTS (
    SELECT NULL
    INTERSECT
    SELECT NULL
)

It is helpful if you want to replicate data from one table to another.