I have the following data
Item | code
item 1 | A
item 1 | B
item 1 | C
But I want to combine codes with a different combination of other codes for the same item
Item | code
item 1 | A
item 1 | B
item 1 | C
item 1 | AB
item 1 | AC
item 1 | BA
item 1 | BC
item 1 | CA
item 1 | CB