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Top Forums Shell Programming and Scripting Join, merge, fill NULL the void columns of multiples files like sql "LEFT JOIN" by using awk Post 303040811 by yjacknewton on Thursday 7th of November 2019 07:24:16 AM
Old 11-07-2019
Join, merge, fill NULL the void columns of multiples files like sql "LEFT JOIN" by using awk

Hello,

This post is already here but want to do this with another way
Merge multiples files with multiples duplicates keys by filling "NULL" the void columns for anothers joinning files

file1.csv:

Code:
1|abc
1|def
2|ghi
2|jkl
3|mno
3|pqr

file2.csv:

Code:
1|123|jojo
1|NULL|bibi
3|789|zaza
3|012|NULL

file3.csv:

Code:
2|1a2b|1994|US
3|3c4e|1995|MG
4|5f6g|1996|FR

My desired output is like this, conserve the duplicate key and fill it with the data of anothers files, and the void columns is filling by NULL:

result.csv
Code:
1|abc|123|jojo|NULL|NULL|NULL
1|def|123|jojo|NULL|NULL|NULL
1|abc|NULL|bibi|NULL|NULL|NULL
1|def|NULL|bibi|NULL|NULL|NULL
2|ghi|NULL|NULL|1a2b|1994|US
2|jkl|NULL|NULL|1a2b|1994|US
3|mno|789|zaza|3c4e|1995|MG
3|pqr|789|zaza|3c4e|1995|MG
3|mno|012|NULL|3c4e|1995|MG
3|pqr|012|NULL|3c4e|1995|MG
4|NULL|NULL|NULL|5f6g|1996|FR

I already found code with JOIN but I want to do this with AWK
This is the "join" command :

Code:
join -t \| -a 1 -a 2 -e 'NULL' -o 0 1.2 1.3 1.4 2.2 2.3 2.4 \ 
\;(join -t \| -a 1 -a 2 -e 'NULL' -o 0 1.2 2.2 2.3 file1 file2) file3

Is there an idea with awk for more performance?
 

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JOIN(1) 						      General Commands Manual							   JOIN(1)

NAME
join - relational database operator SYNOPSIS
join [ options ] file1 file2 DESCRIPTION
Join forms, on the standard output, a join of the two relations specified by the lines of file1 and file2. If file1 is `-', the standard input is used. File1 and file2 must be sorted in increasing ASCII collating sequence on the fields on which they are to be joined, normally the first in each line. There is one line in the output for each pair of lines in file1 and file2 that have identical join fields. The output line normally con- sists of the common field, then the rest of the line from file1, then the rest of the line from file2. Fields are normally separated by blank, tab or newline. In this case, multiple separators count as one, and leading separators are dis- carded. These options are recognized: -an In addition to the normal output, produce a line for each unpairable line in file n, where n is 1 or 2. -e s Replace empty output fields by string s. -jn m Join on the mth field of file n. If n is missing, use the mth field in each file. -o list Each output line comprises the fields specifed in list, each element of which has the form n.m, where n is a file number and m is a field number. -tc Use character c as a separator (tab character). Every appearance of c in a line is significant. SEE ALSO
sort(1), comm(1), awk(1) BUGS
With default field separation, the collating sequence is that of sort -b; with -t, the sequence is that of a plain sort. The conventions of join, sort, comm, uniq, look and awk(1) are wildly incongruous. JOIN(1)
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