SQL: change column datatype

in this note to self, i need have a table where a column (COL2) is an NVARCHAR, and it need to become an NCLOB:

CREATE table TABLENAME_TEMP as select * from TABLENAME;
ALTER table TABLENAME drop COLUMN COL2;
DELETE from TABLENAME;
ALTER table TABLENAME add (COL2 NCLOB NOT NULL);
-- at this point the columns may not line up, so specify order...
INSERT into TABLENAME TN (TN.COL1, TN.COL3, TN.COL2) select * from TABLENAME_TEMP;
COMMIT;
DROP table TABLENAME_TEMP;

now the table TABLENAME has a column which is an NCLOB, yey!s