select sum(f2)
from
(
select f2, rownumber() over(partition by f1) rn
from t1
) a
where rn= 1 ;

with a as
(
select f2, rownumber() over(partition by f1) rn
from t1
)
select *
from table (
values
(
  (select count( 1 ) from (select  1  from t1 group by f1 having count( 1 )= 1 ) b)
, (select sum(f2) from a where rn= 1 )
, (select sum(f3) from t1)
) 
) b (v1, v2, v3)

WITH a AS (SELECT TRNID FROM PENSTRAN.TRANSITS WHERE LAWRSLCOD<> 1  AND PFRRSLCOD IN( 1 , 2 ))
SELECT * FROM TABLE(VALUES(
(SELECT COUNT(*) FROM a),
(SELECT SUM(TICSUM) FROM PENSTRAN.TICKETS WHERE TRNID IN a),
(SELECT SUM(EXPNDLVRY) FROM PENSTRAN.TRANSITS WHERE TRNID IN a)
)) AS b(v1,v2,v3)