How to compare two columns of two csv files with awk? - awk

Question

I have two csv files I need to compare against one column.
My member.csv file looks like:
ID|lastName|firstName
01|Lastname01|Firstname01
02|Lastname02|Firstname02
The second file check-ID.csv looks like:
Lastname01|Name01|pubID01|Hash01
Lastname02|Name02|pubID02|Hash02a
Lastname03|Name03|pubID03|Hash03
Lastname02|Name02|pubID02|Hash02b
Lastname01|Name01|pubID01|Hash01b
--> Lastname03 is not in my member.csv !
What I want is to check if the value of the first column of check-ID.csv is equal to value of second column in member.csv.
My attempt with script.awk is
NR==FNR{a[$1]=$1; b[$1]=$0; next}
$2==a[$1]{ delete b[$1]}
END{for (i in b ) print b[i]}
executing with
awk -f script.awk check-ID.csv member.csv
The problem is that the result is not filtered.
I like to get a filtered and sorted output so only members are listed like this:
Lastname01|Name01|pubID01|Hash01
Lastname01|Name01|pubID01|Hash01b
Lastname02|Name02|pubID02|Hash02a
Lastname02|Name02|pubID02|Hash02b
Any help appreciated!

Answer 1

Could you please try following. I think you were close only thing is you could change your Input_files reading sequence. Where I am reading members Input_file first and then check-ID.csv because later Input_file has all details in it which needs to be printed and we need to only check for 2nd field from members Input_file.
awk '
BEGIN{
FS="|"
}
FNR==NR{
a[$2]
next
}
($1 in a)
' members.csv check-ID.csv |
sort -t'|' -k1
Explanation: Adding detailed explanation for above.
awk ' ##Starting awk program from here.
BEGIN{ ##Starting BEGIN section of this program from here.
FS="|" ##Setting field separator as | here.
}
FNR==NR{ ##Checking condition if FNR==NR which will be TRUE when first Input_file named members.csv is being read.
a[$2] ##Creating array a with index 2nd field here.
next ##next will skip all further statements from here.
}
($1 in a) ##Checking condition if 1st field is preent in a then print that line.
' members.csv check-ID.csv | ##Mentioning Input_file names here and sending its output to sort command.
sort -t'|' -k1 ##Sorting output(which we got from awk command above) by setting separator as | and by first field.