def get_field_select(self, fld, alias=None):
        sel_fmt = self.get_select_format(fld)
        if fld in self.custom_select:
            field_sel = sel_fmt % self.custom_select[fld]
        else:
            field_sel = sel_fmt % self._field_column(fld, alias)
        return field_sel
Returns the SELECT SQL string for the given field.  Figures out
dataset/ETHPy150Open dcramer/django-compositepks/django/contrib/gis/db/models/sql/query.py/GeoQuery.get_field_select