Off topic:Manipulate output join command linux

Question

[marlenejensen]

Hey guys, I used the join command to join two tab separated text files on a common field. This worked perfectly fine except for the output. I expexted something like:

File A:

1 A
2 B
3 C

File B:

1 a
2 B
3 C 

New file:
1 Aa
2 Bb
3 Cc

However, I got an output file which printed the common field of file B below the field of file A instead of right next to it:

1 A
a
2 B
b
3 C
c

I have no clue why and played around with the ouput parameter but nothing worked so far. Do you have an idea how I can change that? Thanks in advance!