select stat_date, model_name, obj_type, cnt, st_dt
from
  (select trunc(stat_date) stat_date, model_name, obj_type, sum(cnt) cnt,
     to_char(trunc(stat_date), 'dd.mm') st_dt
   from t_object_stat
   group by trunc(stat_date), obj_type, model_name
   union all
   select trunc(stat_date) stat_date, 'Все модели' model_name, obj_type, sum(cnt) cnt,
     to_char(trunc(stat_date), 'dd.mm') st_dt
   from t_object_stat
   group by trunc(stat_date), obj_type)
where :P701_MDL_SLCT in (model_name, 'Все модели')

select stat_date, model_name, obj_type, cnt, st_dt
from
  (select trunc(stat_date) stat_date, model_name, obj_type, sum(cnt) cnt,
     to_char(trunc(stat_date), 'dd.mm') st_dt
   from t_object_stat
   group by trunc(stat_date), obj_type, model_name
   union all
   select trunc(stat_date) stat_date, 'Все модели' model_name, obj_type, sum(cnt) cnt,
     to_char(trunc(stat_date), 'dd.mm') st_dt
   from t_object_stat
   group by trunc(stat_date), obj_type)
where /*:P701_MDL_SLCT*/ 'Все модели' in (model_name, 'Все модели')

STAT_DATE  MODEL_NAME       OBJ_TYPE  CNT ST_DT
11.04.2019 Бизнес-глоссарий GLOSSARY   2  11.04

select model_name, model_name mdl_nm
from
  (select model_name, rownum
   from
     (select unique model_name
      from t_object_stat)
   union all
   select 'Все модели', 0 from dual
   order by 2)