use strict;
use warnings;
[download]

and use placeholders in your sql. Put a ? in your sql where you would liek to put a value, then when you call execute pass the values.

#!/usr/bin/perl

# This script reads a file and creates 2 variables with it by using a 
+hash.
# the data is in 2 columns. Column1=msisdn Column2=DeletionDate
# This script may be helpful if expanded to a loop and db query for fi
+guring
# last possible active date.
#
#  Sample of the file read by script
#  19992507638 deletions.20060723
#  19993017551 deletions.20060723



use strict;
use warnings;
use DBI;

my $database = "chai";
my $hostname = "localhost";
my $port = "3306";
my $username = "bonezer";
my $password = 'monezer';

my $dsn = "DBI:mysql:database=$database;host=$hostname;port=$port";
my $dbh = DBI->connect($dsn, $username, $password) or die("Could not c
+onnect!");

my $sql = "select to_days(substring( ?,11)) - to_days(lastactive)  fro
+m user where number = ? into OUTFILE '/tmp/sp'";
my $sth = $dbh->prepare($sql);

open(DATA, "/tmp/SEOUL_NUMBERS") or die "Failed to open /tmp/SEUL_NUMB
+ERS file: $!";
my %hash;
while( <DATA> ) {
    @elements = split / /, $_;
    $hash{ $elements[0] } = $elements[1];
    $hash{ $elements[1] } = $elements[1];
    $sth->execute($elements[1], "$elements[0]\n");
}
$dbh->disconnect;
[download]

It's untested, but hopefully you can see the use of strict, warnings, and placeholders as well as prepared SQL statements. Cheers!