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create table your_table (transactiontime) as
select '42499' from dual;
1 rows affected
select to_number(to_date(transactiontime, 'hh24ss'))
from your_table
ORA-01850: hour must be between 0 and 23
select to_date(to_number(transactiontime), 'sssss') as result
from your_table
| RESULT |
|---|
| 01-MAY-23 |
select to_char(to_date(to_number(transactiontime), 'sssss'), 'YYYY-MM-DD HH24:MI:SS') as result
from your_table
| RESULT |
|---|
| 2023-05-01 11:48:19 |
select to_char(to_date(to_number(transactiontime), 'sssss'), 'HH24:MI:SS') as result
from your_table
| RESULT |
|---|
| 11:48:19 |
select numtodsinterval(to_number(transactiontime), 'SECOND') as result
from your_table
| RESULT |
|---|
| +000000000 11:48:19.000000000 |
select to_number(transactiontime) * interval '1' second as result
from your_table
| RESULT |
|---|
| +000000000 11:48:19.000000000 |
select to_char(to_number(transactiontime) * interval '1' second, 'HH24:MI:SS') as result
from your_table
| RESULT |
|---|
| +000000000 11:48:19.000000000 |
select substr(to_number(transactiontime) * interval '1' second, 12, 8) as result
from your_table
| RESULT |
|---|
| 11:48:19 |