Премахване на крайната десетична нула

Вашите примери показват два различни формата – един за десетични числа и друг за цели числа.

with sampledata as
  (select 0.23 as rowa from dual
union all select 0.2350 from dual
union all select 0.1000 from dual
union all select 1.250 from dual
union all select 1200 from dual
union all select 1.300 from dual
 )
select TO_CHAR(rowa
              ,CASE WHEN rowa = TRUNC(rowa)
               then 'fm999999999999999990'
               else 'fm999999999999999990D999'
               end) as rowa
from sampledata;

ROWA
=====
0.23
0.235
0.1
1.25
1200
1.3