In this post, you’ll learn more about the Oracle ErrorORA-27423: calendar clause string specified more than once with the details on why you receive this error and the possible solution to fix it.
Oracle Error Description
ORA-27423: calendar clause string specified more than once
Reason for the Error ORA-27423: calendar clause string specified more than once
The calendar definition contained a clause that was specified twice or more times.
How to fix the Error ORA-27423: calendar clause string specified more than once ?
You can fix this error in Oracle by following the below steps
Append the values in the second clause to the first clause and remove the second clause.