UNIX for Dummies Questions & Answers

Hi, I need help with the join command
I have 2 files that I want to join on multiple fields.
I want to return all records from file 1
I also want empty fields in my joined file if there isn't a match in file 2

I have already sorted them so I know they are in the same order.

Code:

file1  field 3 matches to file2  field 1 
file1  field 4 matches to file2  field 2
file1  field 5 matches to file2  field 3

If I only had to match file1 field 3 to file2 field 1 this would work perfectly

Code:

join -t "|"   -a1 -j1 3 -j2 1  -o 1.3 1.4 1.5 2.1 2.2 2.3

I get output with the empty fields if no matching record exists.

Code:

1 |a|X|||
2 |a|Z|2 |a|Z

But.. I need to match on multiple fields and I have no idea how to do that.

Thanks!