ТЕМА:

select concat(regexp_substr('0.47', '[^.]*'),substr('0.47', instr('0.47', '.'))*0.6) from dual
0.282
select concat(regexp_substr('2.47', '[^.]*'),substr('2.47', instr('2.47', '.'))*0.6) from dual
2.282

select concat(regexp_substr('24', '[^.]*'),substr('24', instr('24', '.'))*0.6) from dual
2414.4

with s as
(select '0.47' str from dual union all
 select '2.47' str from dual union all
 select '24.47' str from dual 
)
select substr(str, 1, instr(str, '.') - 1)  || ':' || substr((substr(str, instr(str, '.') + 1) * 0.6), 1, 2)
from s

WITH t AS (SELECT 0.47 num FROM dual UNION ALL
           SELECT 2.47 FROM dual UNION ALL
           SELECT 24 FROM dual)
SELECT floor(num)+(num-floor(num))*0.6 FROM t

select substr(str, 1, instr(str, '.') - 1)  || ':' || substr((substr(str, instr(str, '.') + 1) * 0.6), 1, 2)
from s

select substr(str, 1, instr(str, '.') - 1) || ':' || to_char(substr(str, instr(str, '.') + 1) * 0.6, '09')
from s

WITH t AS (SELECT 0.47 num FROM dual UNION ALL
           SELECT 2.47 FROM dual UNION ALL
           SELECT 24 FROM dual)
SELECT floor(num)||':'||lpad(round((num-floor(num))*60),2,'0') FROM t

with t as 
  (select 24 num from dual
    union all
   select 0.47 from dual
    union all
   select 16.17 from dual )
select to_char(trunc(num) + mod(num, 1)*0.6, 'fm00D00', 'nls_numeric_characters='': ''')
  from t;