Question

If not, is there an alternate way to switch through SELECT statements using a CASE or IF/THEN identifier WITHOUT putting the statement in a scalar variable first?

Is there a way to format this without using IS and using an = sign for it to work?

    SELECT ID FROM TABLE WHERE ID = Null

Answer 1

No. NULL isn’t a value. Think of NULL as a condition, with IS NULL or IS NOT NULL is testing for this condition.

In this example you can test for the actual value, or lack of value represented by a conditon

WHERE
   (X IS NULL OR X = @X)

OR

WHERE
  (@X IS NULL OR X = @X)

Or test for your definite conditions first:

WHERE
    CASE X
      WHEN 1 THEN
      WHEN 2 THEN
      ELSE --  includes NULL
   END = ...

Your question is abstract so hard to give a more precise answer.

For example, are you having problems with NOT IN and NULL? If so, use NOT EXISTS.