I face with that error message while I tried to drop column on my compressed tables which in exists in my Exadata.

Bad news is, there is no solution in 10g release. But there are some workaround options available for can pass this error.

What are those options? These are:

  • Upgrade your db to 11gR2
  • Can keep unused columns on tables
  • You may recreate table
  • Do not to use compress options

For 11g and forward database version, you can follow my demo:

oracle@helios> create table test_table compress as select * from dba_users;
Table created.

oracle@helios> alter table test_table add name varchar2;
Table altered.
oracle@helios> alter table test_table drop column name;
alter table test_table drop column name
*
ERROR at line 1:
ORA-39726: unsupported add/drop column operation on compressed tables
oracle@helios> alter table test_table set unused column name;
Table altered.
oracle@helios> alter table test_table drop unused columns;
Table altered.

If you still keep hitting same error you may hit bug 9163477. For details please review below MOS notes.

Reference:
Error ORA-39726 Drop Column Operation On Compressed Tables 10.2 Release [ID 1068820.1]
Bug 9163477 – error ora-39726 while dropping column on compressed partitioned table [ID 9163477.8]