How to merge two file based on multiple Keys (Without using JOIN)

[manish607]

I have two file. I want to have them merged based of 2 keys. There can be multiple records having the same key. if the second file doesn't have a record for the Key, the firse file record will be present in the output will blank for second file.

How can we do it in Awk without using unix JOIN.

Main file
20,2,A
10,2,B
20,3,C
10,2,D
20,3,E
10,3,F

Reference file
10,1,A1
10,2,A2
10,3,A3
20,2,B1

Output file
B1,20,2,A
A2,10,2,B
,20,3,C
A2,10,2,D
,20,3,E
A3,10,3,F

 

[manish607]

Ignore this POST. I figured it out myself.