mysql group by two columns either way

Question

Is it possible to use group by for two columns where they can be group either way?

Example:

MyTable

Column1 | Column2
      1         2
      2         1
      1         3
      3         1
      3         2
      4         5

Result:

Column1 | Column2
      1         2
      1         3
      3         2
      4         5

As you can see, it groups the 2 columns even though interchanged. but should still get the rows that doesn't have a partner.

Answer 1

select
least(Column1, Column2),
greatest(Column1, Column2)
from
Table1
group by 
least(Column1, Column2),
greatest(Column1, Column2)

• see it working live in an sqlfiddle
• read more about the functions here