is there a way to return text based on two fields.

IF field 1 = a
AND field 2 = 1
THEN result = x

IF field 1 = a
AND field 2 = 2
THEN result = y

IF field 1 = a
AND field 2 = 3
THEN result = z

IF field 1 = b
THEN result = BLANK

Is this possible.