use warnings;
use strict;
use DBI;

my $dbh = DBI->connect("dbi:Pg:dbname=pdqtest;host=localhost", 
  "Owner", "",
  {RaiseError=>1},
);

dbh->do("create table mytmptbl (fld1 timestamp, fld2 integer)");
my $sql = qq{ INSERT INTO mytmptbl VALUES (
    current_timestamp,
    ?
    )
    };

my $var = 3;
$dbh->do($sql, undef, $var);

$dbh->disconnect;