Change Column from Varchar2 to CLOB


SQL>alter table test_table add clob_column CLOB;

Table altered.

SQL> update test_table set clob_column = current_varchar_column;

xx rows updated.

SQL> alter table test_table drop column current_varchar_column;

Table altered.

SQL> alter table test_table rename column clob_column to current_varchar_column;

Table altered.