compare column a to b and b to a

[ayazgreat]

An example a column has values 1,3,4,6,9,11,12 and b column has values 1,2,3,7,9,10,13
When compare col b from col a so result is 2,7,10,13
When compare col a to col b so result is 4,6,11,12

[Rick Rothstein]

An example a column has values 1,3,4,6,9,11,12 and b column has values 1,2,3,7,9,10,13
When compare col b from col a so result is 2,7,10,13
When compare col a to col b so result is 4,6,11,12

Are these examples of real values you have? If so, what is the maximum value that can appear in a column? Depending on your two answers to these questions, there may be a relatively simple code solution. However, if those are values that you actually have, could you post an example with the real values? Again, depending on what they are, there again, may be a relatively simple code solution.