Oracle Error ORA-39271: Cannot alter substitutability of column: string

Oracle Error Message

ORA-39271: Cannot alter substitutability of column: string

Reason for the Error

DBMS_METADATA_DIFF was comparing two table columns. This error may occur because the first column is substitutable and the second column is not, or because the first column is OF TYPE and the second column is substitutable.

Solution

The difference cannot be eliminated with an SQL ALTER statement.