Hi, what about this solution:

#! /usr/bin/perl -l
use strict;
use warnings;

my @parameters;
my @operators;
my @value1;
my @value2;

while ( my $line = <DATA> ) {
    
    my ( $param, $operator, $value1, $value2 ) = split /\s/, $line;
    
    push @parameters, $param;
    push @operators,  $operator;
    push @value1,     $value1;
    push @value2,     defined $value2 ? $value2 : '';
    # if $operator is not 'between' $value2 shouldn't be defined, so j
+ust add empty string
    # maybe you want to check $operator additionally
}

# fill your variables instead of printing
print join '|', @parameters;
print join '|', @operators;
print join '|', @value1;
print join '|', @value2;

__DATA__
ID1 > 66
ID2 < 7
ID3 between 6 10
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