What are few Oracle DDL statements or commands ?

Below are few  DDL commands to create, alter, drop, and rename tables.
CREATE TABLE

• Create a table.
• Create a table based on another table by using a subquery.

 

ALTER TABLE

• Modify table structures.
• Change column widths, change column data types, and add columns.

 

DROP TABLE

• Remove rows and a table structure.
• Once executed, this statement cannot be rolled back.

 

RENAME

• Rename a table, view, sequence, or synonym.

TRUNCATE

• Remove all rows from a table and release the storage space used by the table.

COMMENT

•  Add a comment to a table or a column.
• Query the data dictionary to view the comment.

For more details refer below link :

Oracle 9i Tutorial