package MusicDBI;
use base 'Class::DBI';
use SQL::Abstract;

__PACKAGE__->set_sql(
  count_where => 'SELECT COUNT(*) FROM __TABLE__ %s'
);

sub count_where { 
    my $class = shift;
    my $where = (ref $_[0]) ? $_[0]          : { @_ };
    my $attr  = (ref $_[0]) ? $_[1]          : undef;
    my $order = ($attr)     ? delete($attr->{order_by}) : undef;

    $class->can('sql_count_where') or do {
        require Carp;
        Carp::croak("$class should set_sql(count_where => ...)");
    };
    my $sql = SQL::Abstract->new(%$attr);
    my($phrase, @bind) = $sql->where($where, $order);
    my $count = $class->sql_count_where($phrase)->select_val(@bind);

}