use DBI;
my $dbh = DBI->connect(
  "dbi:Pg:host=$host;database=$database",
  $user,
  $password,
  {
    AutoCommit => 0,
    RaiseError => 1,
  },
) or die "Can't connect: $DBI::errstr";

my $data = $dbh->selectall_arrayref(qq{
  SELECT MAX(price) as max_price
  FROM data_log
  WHERE price_date > now()::date - 5
    AND to_char(price_date, 'HH24') = '06'
}) or die "Cannot prepare: $DBI::errstr";

print $data->[0][0];