Pfthb

I have three files. I need to join them based on one column and perform some transformations.

file1.dat (Column 1 is used for joining)

123,is1,ric1,col1,smbc1 
123,is2,ric1,col1,smbc1 
234,is3,ric3,col3,smbc2 
345,is4,ric4,,smbc2 
345,is4,,col5,smbc2 

file2.dat (Column 1 is used for joining)

123,abc 
234,bcd 

file3.dat (Column 4 is used for joining)

r0c1,r0c2,r0c3,123,r0c5,r0c6,r0c7,r0c8 
r2c1,r2c2,r2c3,123,r2c5,r2c6,r2c7,r2c8 
r3c1,r3c2,r3c3,234,r3c5,r3c6,r3c7,r3c8 
r4c1,r4c2,r4c3,345,r4c5,r4c6,r4c7,r4c8 

Expected Output (output.dat)

123,r0c5,is1,ric1,smbc1,abc,r0c8,r0c6,col1,r0c7,r0c1,r0c2,r0c3 
123,r0c5,is2,ric1,smbc1,abc,r0c8,r0c6,col1,r0c7,r0c1,r0c2,r0c3 
123,r2c5,is1,ric1,smbc1,abc,r2c8,r2c6,col1,r2c7,r2c1,r2c2,r2c3 
123,r2c5,is2,ric1,smbc1,abc,r2c8,r2c6,col1,r2c7,r2c1,r2c2,r2c3 
234,r3c5,is3,ric3,smbc2,bcd,r3c8,r3c6,col3,r3c7,r3c1,r3c2,r3c3 
345,r4c5,is4,ric4,smbc2,N/A,r4c8,r4c6,N/A,r4c7,r4c1,r4c2,r4c3 
345,r4c5,is4,N/A,smbc2,N/A,r4c8,r4c6,col5,r4c7,r4c1,r4c2,r4c3 

I wrote the following awk command.

awk '
BEGIN FS=OFS=","
FILENAME == ARGV[1] temp_join_one[$1] = $2"
FILENAME == ARGV[2] exchtbunload[$1] = $2; next
FILENAME == ARGV[3] ");
v3=(array_temp_join_one[1]==""?"N/A":array_temp_join_one[1]);
v4=(array_temp_join_one[2]==""?"N/A":array_temp_join_one[2]);
v5=(array_temp_join_one[4]==""?"N/A":array_temp_join_one[4]);
v6=(exchtbunload[$4]==""?"N/A":exchtbunload[$4]);
v9=(array_temp_join_one[3]==""?"N/A":array_temp_join_one[3]);
v11=($2=""?"N/A":$2);
print $4, $5, v3, v4, v5, v6, $8, $6, v9, $7, $1, v11, $3 >
"output.dat" 
' file1.dat file2.dat file3.dat

I need to join all three files.

The final output file should have all the values from file3 irrespective of whether they are in other two files and the corresponding columns should be empty(or N/A) if it is not present in other two files. (The order of the columns is not a very big problem. I can use awk to rearrange them.)

But my problem is, as the key is not unique, I am not getting the expected output. My output has only three lines.

I tried to apply the solution suggested using join condition. It works with smaller files. But the files I have are close to 3-5 GB in size. And they are in numerical order and not lexicographical order. Sorting them looks like would take lot of time.

Any suggestion would be helpful.

Thanks in advance.

with join, assuming files are sorted by the key.

$ join -t, -1 1 -2 4 <(join -t, -a1 -a2 -e "N/A" -o1.1,1.2,1.3,1.4,1.5,2.1 file1 file2) 
 file3 -o1.1,2.5,1.2,1.3,1.5,1.6,2.8,2.6,1.4,2.7,2.2,2.3

123,r0c5,is1,ric1,smbc1,123,r0c8,r0c6,col1,r0c7,r0c2,r0c3
123,r2c5,is1,ric1,smbc1,123,r2c8,r2c6,col1,r2c7,r2c2,r2c3
123,r0c5,is2,ric1,smbc1,123,r0c8,r0c6,col1,r0c7,r0c2,r0c3
123,r2c5,is2,ric1,smbc1,123,r2c8,r2c6,col1,r2c7,r2c2,r2c3
234,r3c5,is3,ric3,smbc2,234,r3c8,r3c6,col3,r3c7,r3c2,r3c3
345,r4c5,is4,ric4,smbc2,N/A,r4c8,r4c6,N/A,r4c7,r4c2,r4c3
345,r4c5,is4,N/A,smbc2,N/A,r4c8,r4c6,col5,r4c7,r4c2,r4c3

I really like the answer using join, but it does require that the files are sorted by the key column. Here's a version that doesn't have that restriction. Working under the theory that the best tool for doing database-like things is a database, it imports the CSV files into tables of a temporary SQLite database and then runs a SELECT on them to get your desired output:

(edit: Revised version based on new information about the data)

#!/bin/sh
# Usage: ./merge.sh file1.dat file2.dat file3.dat > output.dat
file1=$1
file2=$2
file3=$3

rm -f scratch.db
sqlite3 -batch -noheader -csv -nullvalue "N/A" scratch.db <<EOF | perl -pe 's#(?:^|,)K""(?=,|$)#N/A#g'
CREATE TABLE file1(f1_1 INTEGER, f1_2, f1_3, f1_4, f1_5);
CREATE TABLE file2(f2_1 INTEGER, f2_2);
CREATE TABLE file3(f3_1, f3_2, f3_3, f3_4 INTEGER, f3_5, f3_6, f3_7, f3_8);
.import $file1 file1
.import $file2 file2
.import $file3 file3
-- Build indexes to speed up joining and sorting gigs of data.
CREATE INDEX file1_idx ON file1(f1_1);
CREATE INDEX file2_idx ON file2(f2_1);
CREATE INDEX file3_idx ON file3(f3_4);
SELECT f3_4, f3_5, f1_2, f1_3, f1_5, f2_2, f3_8, f3_6, f1_4, f3_7, f3_1
 , f3_2, f3_3
FROM file3
LEFT JOIN file1 ON f1_1 = f3_4
LEFT JOIN file2 ON f2_1 = f3_4
ORDER BY f3_4;
EOF
rm -f scratch.db

Note: This will use a temporary database file that's going to be the size of all your data and then some because of indexes. If you're space constrained, I have an idea for doing it without temporary files, given the information that the join columns are sorted numerically, but it's enough work that I'm not going to bother unless asked.