[Dbix-class] Unknown column in 'group statement'

[Anthony Gladdish]

Hi,

Using:
Perl 5.10.
DBIC 0.08108.

1. My result source tables with relationships are:

Event.pm:
__PACKAGE__->set_primary_key('id');
__PACKAGE__->belongs_to( 'leader' => 'Trainer' ) ;
__PACKAGE__->has_many( 'assistingtrainers' => 'AssistingTrainer', 'event' );
__PACKAGE__->many_to_many('assistants' => 'assistingtrainers', 'trainers' );

AssistingTrainer.pm:
__PACKAGE__->set_primary_key('event','trainer');
__PACKAGE__->belongs_to( 'events' => 'Event', 'event' );
__PACKAGE__->belongs_to( 'trainers' => 'Trainer', 'trainer' );

Trainer.pm:
__PACKAGE__->set_primary_key('id');

2. My ResultSet::Event.pm methods:

sub goEvents {
	my $self  = shift;
	my $where = {};
	$where->{status} = { '&' => 2 };
	return $self->search($where);
}

sub events_during_lookback_period {
	my $self  = shift;	
	my $default_lookback_period = DateTime::Duration->new( years => 3 );	
	my $lookback_period = shift || $default_lookback_period;	
	my $earliest_date = DateTime->now() - $lookback_period;	
	return $self->goEvents()->search_rs(
		{
			-and => [
				start => { '<', DateTime->now() },
				start => { '>', $earliest_date },
			],
	    }
	);
}

sub distinct_assistants {
	my $self  = shift;    
	my $assistants = [];
	my $rs = $self->search_rs(
		undef,
		{
			columns => [ qw/me.id/ ],
            		distinct => 1,            
        		prefetch => [ { 'assistingtrainers' => 'trainers' } ],
			join => [ { 'assistingtrainers' => 'trainers' } ],
        	},
	);
	while ( my $e = $rs->next() ) {	
		foreach my $at ( $e->assistingtrainers() ) {			
			push( @$assistants, $at->trainers );			
		}		
	}
	return $assistants;
}

3. Test case producing error:

$trainers = $schema->resultset('Event')->events_during_lookback_period($lookback_period)->distinct_assistants();

The "distinct_assistants()" chained method is producing error:

DBIx::Class::ResultSet::next(): DBI Exception: DBD::mysql::st execute failed: Unknown column 'assistingtrainers.event' in 'group statement' [for Statement "SELECT me.id, assistingtrainers.event, assistingtrainers.trainer, trainers.id, trainers.name, trainers.email, trainers.phone, trainers.initials, trainers.loginId, trainers.password FROM (SELECT me.id FROM event me WHERE ( ( ( start < ? AND start > ? ) AND status & ? ) ) GROUP BY me.id, assistingtrainers.event, assistingtrainers.trainer, trainers.id, trainers.name, trainers.email, trainers.phone, trainers.initials, trainers.loginId, trainers.password) me LEFT JOIN trainer_assist assistingtrainers ON assistingtrainers.event = me.id LEFT JOIN trainer trainers ON trainers.id = assistingtrainers.trainer WHERE ( ( ( start < ? AND start > ? ) AND status & ? ) ) ORDER BY assistingtrainers.event" with ParamValues: 0='2009-07-23T15:10:02', 1='2006-07-23T15:10:02', 2=2, 3='2009-07-23T15:10:02', 4='2006-07-23T15:10:02', 5=2]

Can anyone see if any schema updates/tweaks are required to make this work?
Or, if I'm missing anything else or if I'm using incorrect syntax?
Or confirm if this is a bug?

Thanks in advance,
Anthony