How to join two CSV files?

Question

Suppose you have one CSV file with 2 fields: ID and email. You have another file with 2 fields: email and name. How can you produce a file with all three fields joined on email?

Answer 1

Revision3:

You must sort both lists on email alphabetically, then join. Given that the email field the 2nd field of file1 and the 1st field of file2:

sort -t , -k 2,2 file1.csv > sort1.csv
sort -t , -k 1,1 file2.csv > sort2.csv
join -t , -1 2 -2 1 sort1.csv sort2.csv > sort3.csv

parameter meaning

-t ,   : ',' is the field separator
-k 2,2 : character sort on 2nd field
-k 1,1 : character sort on 1st field
-1 2   : file 1, 2nd field
-2 1   : file 2, 1st field
>      : output to file

produces

email,ID,name
email,ID,name
...

sorted by email alphabetically.

Note that if any email is missing from either file it will be omitted from the results.

Answer 2

Perhaps it is overkill, but you could import into a database (e.g. OpenOffice Base) as two kinds of tables and define a report that is the desired output.

If the CSV import is a problem, then a spreadsheet program (e.g. OpenOffice Calc) can do the import. The result can then easily be transferred to the database.

Answer 3

As a future reference you might want to start playing around with AWK. It's a very simple little scripting language that exists in some form on every *nix system and its sole mission is life is the manipulation of standard delimited textual databases. With a few lines of throwaway script you can do some very useful things. The language is small and elegant and has a better utility/complexity ratio than anything else I am aware of.

Answer 4

The easiest resolution of the problem - make xlsx from csv and use Vlookup to search for the name in second file :)