Note that this approch changes both 1,2,,3,4 and 1,2,"",3,4 to 1,2,NULL,3,4.

The safe way would be

$ cat test.pl

use 5.18.2;
use warnings;
use Text::CSV_XS qw( csv );

csv (in => csv (
        in             => *ARGV,
        blank_is_undef => 1,
        on_in          => sub { $_ //= "NULL" for @{$_[1]}; },
        ),
     );

$ cat test.csv
1,2,,3,4
1,2,"",3,4

$ perl test.pl test.csv
1,2,NULL,3,4
1,2,,3,4

[download]

Enjoy, Have FUN! H.Merijn

In reply to Re^2: insert null in missing places of csv by Tux
in thread insert null in missing places of csv by ukhare

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