Show DDL for create Oracle DB table

Default long size is only 80. If your DDL is longer you will have to increase the long size to display full DDL. The GET_DDL may not exactly match what was used for creating the table as it will list the default optional settings as well that the actual create table script may have omitted. 

SQL> set long 200000

SQL> select DBMS_METADATA.GET_DDL('TABLE','<your_table_name>') from dual;