How to match column 2 csv file and update column with new data and save it to new file

Question

I have ListIPv6.csv

2001:c00::-2001:dff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1020211200,ZZ,,
2001:e00::-2001:fff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1041379200,ZZ,,
2001:1200::-2001:13ff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1036108800,ZZ,,
2001:1200::-2001:1200:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1042156800,MX,,
2001:1208::-2001:1208:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1044230400,MX,,
2001:1210::-2001:1210:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1095984000,MX,,
2001:1218::-2001:1218:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1120003200,MX,,

and CountryCode.csv

MX, MEXICO
NZ, NEWZOMBIE

I want to update column 6 ListIPv6.csv from column 2 of CountryCode.csv when column 4 of ListIPv6.csv match with column 1 of CountryCode.csv

The expected output of updated ListIPv6.csv will be:

2001:c00::-2001:dff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1020211200,ZZ,,
2001:e00::-2001:fff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1041379200,ZZ,,
2001:1200::-2001:13ff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1036108800,ZZ,,
2001:1200::-2001:1200:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1042156800,MX,,MEXICO
2001:1208::-2001:1208:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1044230400,MX,,MEXICO
2001:1210::-2001:1210:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1095984000,MX,,MEXICO
2001:1218::-2001:1218:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1120003200,MX,,MEXICO

I have used below command but it doesn't fullfill my criteria.

sed -f <(printf 's/%s/%s/g\n' $(<CountryCode.csv)) <(head -n 1000 ListIPv6.csv) >NewListIPv6.csv

Answer 1

Using awk:

awk -F', *' 'NR==FNR{a[$1]=$2;next}{print $0 a[$4]}' CountryCode.csv ListIPv6.csv

The array a is filled with lines of the file CountryCode.csv and then the other file is displayed together with the entries of the array.

Answer 2

Unix can join without an RDBMS:

sort -t , -k 4 ListIPv6.csv | join -a 1 -t , -1 4 -2 1 -o 1.1,1.2,1.3,1.4,1.5,2.2 - CountryCode.csv

giving:

2001:1200::-2001:1200:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1042156800,MX,, MEXICO
2001:1208::-2001:1208:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1044230400,MX,, MEXICO
2001:1210::-2001:1210:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1095984000,MX,, MEXICO
2001:1218::-2001:1218:ffff:ffff:ffff:ffff:ffff:ffff,lacnic,1120003200,MX,, MEXICO
2001:1200::-2001:13ff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1036108800,ZZ,, 
2001:c00::-2001:dff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1020211200,ZZ,,
2001:e00::-2001:fff:ffff:ffff:ffff:ffff:ffff:ffff,iana,1041379200,ZZ,,