#!/usr/bin/perl -w
use strict;
use DBI;
$|++;
my $user = "username";
my $pass = "password";
my $dbnm = "database";
my $table = "table";

my $dbh = DBI->connect("DBI:mysql:$dbnm", $user, $pass);
my $ret = $dbh->selectcol_arrayref("select line_n, word from $table", { Columns => [ 1, 2 ] });
$dbh->disconnect;

my %seen;
my @list = @$ret;
while (@list){
    my $line_n = shift @list;
    my $word = shift @list;

    print $seen{$line_n}++ ? " " : "\n$line_n: ";
    print $word;
}