Primary Key

I created a table using  

create table my_table
as select x, y , y
from d

when I alter the constranint

SQL> alter table my_table
  2 add (constraint my_table_pk primary key (x)); alter table my_table
*
ERROR at line 1:
ORA-02437: cannot enable (ORGANIZATION.MY_TABLE_PK) - primary key violated

anyone know how to alter the primary key without without getting a violation?? Received on Sat Apr 10 1999 - 00:00:00 CDT