Assuming that we have two tables:
Table Q D E a 1 b 2 g 1
Table R D E f 1 b 2 h 3
Show the result of a set difference between tables Q and R. My answer is
D E a 1 g 1
But my classmates said the instructor's answer is
D E a 1 g 1 f 1 h 3
So it looks like symmetric difference rather than the real "difference", which answer is right? My classmates said that the question use the word "Between" so the answer should include two tables, but I do not think so.