SQL Puzzler - Join T and DISTINCT(T)

OK, all you SQL "wizards". I used to hope to count myself amongst your number, until I stumbled onto this little problem. This is *not* a homework problem (although it'd make a darned good one).

First, I'm using Oracle, but this is a general SQL problem.

I have a table, let's call it 'T', with two attributes (A & B), having the following values:

A B

1	x
1	x
1	x
1	y
1	y

I want to join this table with its DISTINCT self on A, also ignoring cases where the DISTINCT B and the regular B column are identical. That is, I want to get:

B B

x	y
x	y
y	x
y	x
y	x

To recap:
Let R = SELECT DISTINCT * from T

Now, I want:
  SELECT R.B T.B
  WHERE R.A = T.A AND R.B != T.B However, I'd like to do these two steps in a *single* (presumably nested) SQL statement. It sounds easy, but it's turning into a nightmare.

I can (and have) done it using ORACLE PL/SQL, by the way.

Questions:

1. Is there a general single SQL statement that will join a table with it's distinct version?
2. Is there an ORACLE SQL*PLUS query to do the same thing (note that ORACLE != SQL)?

--

Matthew Merzbacher	ARPA:	matthew_at_CS.UCLA.EDU
Moo - Moo Moo  		UUCP:	...!{uunet|rutgers|ucbvax}!cs.ucla.edu!matthew
               		This time, *with* the oys