PL/SQL “between x and y” does not work, if y < x. Why?

Question

I have a PL/SQL code like:

case when column between 201203 and 201201
then other_column
end

I know that there are values in column that are

Answer 1

This is ANSI SQL behavior.

 expr1 BETWEEN expr2 AND expr3

translates to

 expr2 <= expr1 AND expr1 <= expr3