Having read your question several times, I can't make heads or tails from it. What is the schema of the database table? How do you store REC2 DATA3 DATA4 2 DATAX with 5 columns and RECZ 5 DATAX with 3 columns? Also, what do you mean by (NEW VALUE) ? Why is the first RECZ numbered with 5, but there's no number for the second RECZ?

If you just want to know how to persist a value across several iterations of a loop, the answer is simple: declare a variable before the loop.

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

my $grouping = q();
while (<DATA>) {
    my @columns = split;
    print "@columns $grouping\n";
    if (@columns > 2) {
        $grouping = $columns[1] if q() eq $grouping;
    } else {
        $grouping = q();
    }
}

__DATA__
REC1 DATAX DATA2 1
REC2 DATA3 DATA4 2
REC3 DATA5 DATA6 3
REC4 DATA7 DATA8 4
RECZ 5
REC1 DATAY DATA2 6
REC2 DATA3 DATA4 7
REC3 DATA5 DATA6 8
REC4 DATA7 DATA8 9
RECZ
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($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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