from django.db.models import Aggregate,CharField

class GroupConcat(Aggregate):
	"""docstring for GroupConcat"""

	function='GROUP_CONCAT'
	template='%(function)s(%(distinct)s%(expressions)s%(ordering)s%(separator)s)'
	def __init__(self, expression,distinct=False,ordering=None,separator=',',**extra):
		super(GroupConcat, self).__init__(expression,
			distinct='DISTINCT ' if distinct else '',
			ordering=' ORDER BY %s' % ordering if ordering is not None else '',
			separator=' SEPARATOR "%s"' % separator,
			output_field=CharField(),
			**extra
			)
		#self.arg = arg
