my $query = "SELECT * FROM lala WHERE moomoo = ?";
my $sth = $dbh->prepare($query);
# at this point, the query string is parsed, and discovers
# that there is one substituion.  The DBI will require one
# argument to the C<exec()> function and complain if it
# doesn't see one.

foreach my $moomoo_val ( @vals ){

  # Note that the query is now cached, and can be
  # re-C<execute()>'d as many times as you wish.
  $sth->execute($moomoo_val);

  while(my $row = $sth->fetchrow_hashref){
    print( join("\t", vals %$row), "\n" );
  }
}