$sth->execute($foo,$bar)
    or die "Couldn't execute query:" . $sth->errstr;

##</code><code>##

 LEVEL | EFFECT
--------------------------------------------
   0     Disable trace
   1     Execution trace (values and errors)
   2     L1 + method and params
   3     L2 + driver level (very detailed)
   4     An insane amount of information

##</code><code>##

	# The main Select
  $sth_main = $dbh->prepare(<<'__EOSQL__');
SELECT DISTINCT t.account_no, 
                t.telephony_id, 
                n.sim, 
                n.mobile_number, 
                s.user_name, 
                s.contract_status, 
                s.dealer, 
                to_char(t.eff_start_date,'DD.MM.YYYY'),
                to_char(s.signed_date,'DD.MM.YYYY'),
                to_char(s.subscr_change_upd,'DD.MM.YYYY'), 
                lpad(s.s_id,7,'0'), 
                to_char(t.eff_start_date,'HH24:MI:SS')
FROM new_sim n, subscription s, tele_period t
WHERE (t.account_no   = n.account_no) AND 
	  (t.telephony_id = n.mobile_number) AND
      (t.account_no   = s.account_no) AND
      (t.telephony_id = s.mobile_number)
ORDER BY t.account_no, t.telephony_id
__EOSQL__

##</code><code>##

# using an array ref instead
$rec = $sth_main->fetchrow_arrayref('NAME_lc')
$sth_imei->execute( $rec->[1], $rec->[0] ) 
    or die $sth_imei->errstr;

# using a hash ref
$rec = $sth_main->fetchrow_hashref('NAME_lc');
$sth_imei->execute( $rec->{telephony_id}, $rec->{account_no})
    or die $sth_imei->errstr;