via DBI you can easily get a list of original rankings for a particular column. The following code gives a mapping of the original ranking to the new ratio ranking (by the way, your result in the g2d_ranking column doesn't seem to be correct: there is a ratio of 1.857)

use strict;

my @old = (237,153,258,231,154,159,141);
my %unique = map {$_ =>1} @old; #just in case the old rankins are not 
+unique
my @ordered = sort keys %unique;
my %map = ();
for my $i (0..$#ordered){
    $map{$ordered[$i]} = $i+1;
}

foreach my $i (@old){
    print $i, "=>",$map{$i}/scalar(@ordered),"\n";
}
__END__
237=>0.857142857142857
153=>0.285714285714286
258=>1
231=>0.714285714285714
154=>0.428571428571429
159=>0.571428571428571
141=>0.142857142857143
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