null values not processed by to_timestamp in oracle sql - sql

Question

I'm trying to load data from a csv with sql-loader. There's one column with date in this format:
2011-12-31 00:00:00.000
I tried it using to_date() but it couldn't handle fractions of second. Therefore I used this:
cast(TO_TIMESTAMP(:DATUM_ONTVANGST, 'YYYY-MM-DD HH24:MI:SS.FF3')as date)
Now I get the error:
ORA-01841: (full) year must be between -4713 and +9999, and not be 0
for null values in the column
Can to_timestamp not handle null values or am I doing something wrong?

Answer 1

This works:
select
cast(TO_TIMESTAMP('2011-12-31 00:00:00.000', 'YYYY-MM-DD HH24:MI:SS.FF3')as date)
from dual
and this also works
select
cast(TO_TIMESTAMP(null, 'YYYY-MM-DD HH24:MI:SS.FF3')as date)
from dual
So there must be some value that is not right format

Answer 2

I think there is space(<field>, ,<field>) in your data which is causing the issue.
Better to use TRIM before using them.
Following are some examples to demonstrate with different values:
-- working fine with correct timestamp values
SQL> SELECT
2 CAST(TO_TIMESTAMP('2019-11-05 00:00:00.000', 'YYYY-MM-DD HH24:MI:SS.FF3') AS DATE) as dt
3 FROM
4 DUAL;
DT
---------
05-NOV-19
-- working fine with a null value
SQL>
SQL> SELECT
2 CAST(TO_TIMESTAMP(NULL, 'YYYY-MM-DD HH24:MI:SS.FF3') AS DATE) as dt
3 FROM
4 DUAL;
DT
---------
-- working fine with an empty value
SQL>
SQL> SELECT
2 CAST(TO_TIMESTAMP('', 'YYYY-MM-DD HH24:MI:SS.FF3') AS DATE) as dt
3 FROM
4 DUAL;
DT
---------
Now showing the error and solution
-- giving an error with space in the value -- Your case
-- might be you are considering it as the null
-- but it is actually a value that is a space character
SQL>
SQL> SELECT
2 CAST(TO_TIMESTAMP(' ', 'YYYY-MM-DD HH24:MI:SS.FF3') AS DATE) as dt
3 FROM
4 DUAL;
CAST(TO_TIMESTAMP(' ', 'YYYY-MM-DD HH24:MI:SS.FF3') AS DATE) as dt
*
ERROR at line 2:
ORA-01841: (full) year must be between -4713 and +9999, and not be 0
-- Solution to your issue -- using TRIM
SQL>
SQL> SELECT
2 CAST(TO_TIMESTAMP(TRIM(' '), 'YYYY-MM-DD HH24:MI:SS.FF3') AS DATE) as dt
3 FROM
4 DUAL;
DT
---------
SQL>
Cheers!!

Answer 3

Building off Ersin's answer, this is the format that worked for me
select
cast(NULL AS TIMESTAMP WITH LOCAL TIME ZONE) as date
from dual