JOIN

[tanuja]

Hi can someone explain its result?

mm:
load * Inline [
A, B
1, a
1, b
2 ,c
0, d];

Right join

nn:
load * Inline [
A, B, C
1, e, ww
2, r, xx
3, t , dd
4,kk,ll
];

exit script ;

[G3S]

SInce it is a right join, mm is getting joined to nn. not the other way around. 
if you  also want the B from table 'mm' then it needs to be renamed to something else. (I named it D)

 is this what you were after?

[BrunPierre]

A Right Join includes all rows from the right table and the matching rows from the left table. If no match is found, the left table's columns will have NULL values.

[anat]

Your output will be right table it self bcz here join key is A and B and no common records BTN 2 tables