Не могу вставить "UNION ALL" в запрос

EXECUTE ('
select distinct h.*,
(SELECT getsezon(h.sezon,h.dateactive,  
           getsezon_tranzit(h.id_shedule,min,
                     '||quote_literal(dater)||', h.t_o)
         )  limit 1) as sezonflag
from
(select 
-- ot
z.id_shedule,
z.id_point as ot_id_point,
z.point_order as ot_point_order,
z.name as ot_name,
z.t_o as t_o,
(select dateactive from av_shedule where del=0 and id=z.id_shedule limit 1
) as dateactive,
(select massezon from av_shedule_sezon where del=0 and id_shedule=z.id_shedule and id_kontr in ('||id_kontr_list||') order by massezon desc limit 1
) as sezon,
--do
 (select min(x.point_order) from av_shedule_sostav x 
      where x.del=0 and x.id_shedule=z.id_shedule and x.point_order>=z.point_order) min,
 (SELECT a.id_point
  FROM av_shedule_sostav a where a.del=0 and a.form=1 and a.id_shedule=z.id_shedule and
  a.point_order>z.point_order and a.form=1  order by a.point_order limit 1 ) as do_id_point, 
 (SELECT a.point_order
  FROM av_shedule_sostav a where a.del=0 and a.form=1 and a.id_shedule=z.id_shedule and
  a.point_order>z.point_order and a.form=1  order by a.point_order limit 1 ) as do_point_order, 
 (SELECT a.name
  FROM av_shedule_sostav a where a.del=0 and a.form=1 and a.id_shedule=z.id_shedule and
  a.point_order>z.point_order and a.form=1  order by a.point_order limit 1 ) as do_name,
 (SELECT a.t_p
  FROM av_shedule_sostav a where a.del=0 and a.form=1 and a.id_shedule=z.id_shedule and
  a.point_order>z.point_order and a.form=1  order by a.point_order limit 1 ) as t_p  
from
(SELECT a.id_shedule,a.id_point,a.name,a.form,a.t_o,a.t_s,a.t_p,a.backout,a.point_order
  FROM av_shedule_sostav a
  where a.del=0 
        and a.form=1 
        and a.id_shedule in
        (
        SELECT distinct on(p.id)
                p.id
           FROM av_shedule p,av_shedule_atp l
          where 
                p.del=0 and 
                l.del=0 and
                l.id_shedule=p.id and
                l.id_kontr in ('||id_kontr_list||') and
                p.active=1 and 
                p.dates<='||quote_literal(dater)||' and
                p.datepo>='||quote_literal(dater)||' and
                p.dateactive<='||quote_literal(dater)||'
        )
        order by a.id_shedule,a.point_order) z) h
  where h.ot_name<>'||quote_literal('')||' and h.do_name<>'||quote_literal('')||' order by h.t_o 
--UNION ALL SELECT t_o FROM av_trip_add ;
 '
--UNION ALL SELECT a.id_shedule FROM av_shedule_sostav 
 );