Why Ansi_nulls does not work?

Question

Assume that I have 2 tables named aTable1, aTable2

aTable1 has userID set to identity and contains the following data:

userID  email          FirstNa         


        

Answer 1

It is documented that it won't work:

SET ANSI_NULLS ON affects a comparison only if one of the operands of the comparison is either a variable that is NULL or a literal NULL. If both sides of the comparison are columns or compound expressions, the setting does not affect the comparison.