Vaše vzorky ukazují dva různé formáty – jeden pro desetinná čísla a jiný pro celá čísla.
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