package My::Table;
use base 'My::Class::DBI';

__PACKAGE__->table('blah');
__PACKAGE__->columns( All => qw/ foo bar baz quid quux / );
__PACKAGE__->columns( Essential => qw/ foo bar / );
__PACKAGE__->columns( Primary => 'foo' );

# assuming we have another table called 'other'..
# this creates a method called sql_method_name
__PACKAGE__->set_sql( method_name => qq( select b.foo, b.bar, o.summat, o.summat_else from blah b left join other o using(foo) where b.quid=?));

sub public_method_name {
    my ($class,$quid) = @_;
    my $sth = $class->sql_method_name();
    $sth->execute($quid);
    return @{$sth->fetchall_arrayref({})};
}