Duplicate names..sql help?

Question

Hi,
I am facing s problem hope you would help
I am running a query that shows me name of employees from a table with their
employee_ids
select emp_id, emp_name from t
EMP_ID     EMP_NAME 
1820       Waugh 
1920       King 
1936       Ric 
1940       Taylor 
2036       Smith 
2123       Paul 
2157       ALi 
2181       Smith 
2189       Joe 
2332       Bichel 
2333       Usman  I want that if there are more than ONE same EMP_NAMES returned by the query,
then query should not show the emp_name but instead should show 'duplicate
name' for matching names
so in my above data the name SMITH has come twice
so my desired output is
EMP_ID     EMP_NAME 
1820       Waugh 
1920       King 
1936       Ric 
1940       Taylor 
2036       DUPLICATE NAME 
2123       Paul 
2157       ALi 
2181       DUPLICATE NAME 
2189       Joe 
2332       Bichel 
2333       Usman  hope this will clear my requirement, I need the fastest and shortest possible
query to achieve this
CREATE TABLE T
(EMP_ID NUMBER(4),
EMP_NAME VARCHAR2(25))
INSERT INTO T VALUES (1820,'Waugh');
INSERT INTO T VALUES (1920,'King');
INSERT INTO T VALUES (1936,'Ric');
INSERT INTO T VALUES (1940,'Taylor');
INSERT INTO T VALUES (2036,'Smith');
INSERT INTO T VALUES (2123,'Paul');
INSERT INTO T VALUES (2157,'ALi');
INSERT INTO T VALUES (2181,'Smith');
INSERT INTO T VALUES (2189,'Joe');
INSERT INTO T VALUES (2332,'Bichel');
INSERT INTO T VALUES (2333,'Usman');
regards,

Answer 1

SQL> select emp_id
  2        ,decode((select count(*)
  3                from   t t2
  4                where  t2.emp_name = t1.emp_name)
  5               ,1, t1.emp_name
  6               ,0, '(name not found)'
  7               ,'DUPLICATE NAME'
  8               ) empname
  9  from t t1;
              EMP_ID EMPNAME
                1820 Waugh
                1920 King
                1936 Ric
                1940 Taylor
                2036 DUPLICATE NAME
                2123 Paul
                2157 ALi
                2181 DUPLICATE NAME
                2189 Joe
                2332 Bichel
                2333 Usman
11 rows selected.