views.py

    #---------------------------------------------------------------------------
    def get_queryset(self):
        qs = self.filter_by_vcs(super().get_queryset())
        qs = qs.annotate(
            postings=Count(
                'opportunity',
                filter=Opportunity.objects.active_predicate(),
                distinct=True,
            )
        )
        self.ordering = 'member__name'
        ordering = ['member__name']
        o = self.request.GET.get('o', '')
        if o in ['postings', '-postings']:
            self.ordering = o
            ordering = [o, 'member__name']
        qs = qs.order_by(*ordering)
        qs.select_related('member')
        return qs