with sum as (select ud.id,sum(data_volume) total
from mediation.udr ud
inner join mediation.meter_reading mr on ud.cdr_id = mr.id
group by ud.id)
(select total from sum)

select
act.actno,
act.actid,
act.actname,
dom.domname,
case when act.status =0 then 'Active'
when act.status =1 then 'Blocked'
when act.status = 15 then 'Expired'
when act.status = 17 then 'Cloesd'
when act.status = 18 then 'Closed-Chnage Subs'
else 'Disabled' end as acct_status,
case when s.status =0 then 'Active'
when s.status =1 then 'Blocked'
when s.status = 15 then 'Expired'
when s.status = 17 then 'Cloesd'
when s.status = 18 then 'Closed-Chnage Subs'
else 'Disabled' end as subs_status,
current_meter_reading,
m.subsno,
acq_date,
actacl_value ,
(select min(previous_meter_reading) previous_meter_reading from mediation.meter_reading m1
where acq_date::date>= '2019-08-01' ::date and acq_date::date<= '2019-08-19' ::date and actacl_value=m.actacl_value),
actacl.intial_meter_reading
from (select max(current_meter_reading) current_meter_reading,max(subsno) subsno, max(acq_date) acq_date,actacl_value from mediation.meter_reading m
where acq_date::date>= '2019-08-01'::date and acq_date::date<= '2019-08-19'::date
group by actacl_value) as m ,
subs s,
account act ,
actacl,
ssgdom dom
where act.actno=s.actno
and s.subsno=m.subsno
and actacl.value = m.actacl_value
and dom.domno = act.domno
and actacl.status=0 limit 10;

ERROR:  syntax error at or near "select"
LINE 3: select
        ^