ORA-01843: not a valid month
Oracle PL/SQL error message: ORA-01843: not a valid month.
Cause:
A date specified an invalid month. Valid months are: January-December, for format code MONTH, and Jan-Dec, for format code MON.
Solution:
Enter a valid month value in the correct format.
Example:
SELECT TO_DATE('2015.26.12','YYYY.MM.DD') FROM dual;
Output:
ORA-01843: not a valid month
Correct:
SELECT TO_DATE('2015.12.26','YYYY.MM.DD') FROM dual;
Output:
26-DEC-2015 00:00:00