SQL>
SQL> -- create employee table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(20 BYTE),
  4    Last_Name          VARCHAR2(20 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(20 BYTE),
  9    Description        VARCHAR2(80 BYTE)
 10  )
 11  /

Table created.

SQL>
SQL> -- prepare data
SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2               values ('01','Jason',    'Martin',  to_date('19960725','YYYYMMDD'), to_date('20060725','YYYYMMDD'), 1234.56, 'Toronto',  'Programmer')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('02','Alison',   'Mathews', to_date('19760321','YYYYMMDD'), to_date('19860221','YYYYMMDD'), 2234.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('03','James',    'Smith',   to_date('19781212','YYYYMMDD'), to_date('19900315','YYYYMMDD'), 2324.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('04','Celia',    'Rice',    to_date('19821024','YYYYMMDD'), to_date('19990421','YYYYMMDD'), 3334.78, 'Vancouver','Manager')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary,  City,       Description)
  2                values('05','Robert',   'Black',   to_date('19840115','YYYYMMDD'), to_date('19980808','YYYYMMDD'), 4334.78, 'Vancouver','Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('06','Linda',    'Green',   to_date('19870730','YYYYMMDD'), to_date('19960104','YYYYMMDD'), 5334.78,'New York',  'Tester')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('07','David',    'Larry',   to_date('19901231','YYYYMMDD'), to_date('19980212','YYYYMMDD'), 6334.78,'New York',  'Manager')
  3  /

1 row created.

SQL> insert into Employee(ID,  First_Name, Last_Name, Start_Date,                     End_Date,                       Salary, City,        Description)
  2                values('08','James',    'Cat',     to_date('19960917','YYYYMMDD'), to_date('20020415','YYYYMMDD'), 7334.78,'Vancouver', 'Tester')
  3  /

1 row created.

SQL>
SQL>
SQL>
SQL> -- display data in the table
SQL> select * from Employee
  2  /

ID   FIRST_NAME           LAST_NAME            START_DAT END_DATE      SALARY CITY                 DESCRIPTION
---- -------------------- -------------------- --------- --------- ---------- -------------------- --------------------------------------------------------------------------------
01   Jason                Martin               25-JUL-96 25-JUL-06    1234.56 Toronto              Programmer
02   Alison               Mathews              21-MAR-76 21-FEB-86    2234.78 Vancouver            Tester
03   James                Smith                12-DEC-78 15-MAR-90    2324.78 Vancouver            Tester
04   Celia                Rice                 24-OCT-82 21-APR-99    3334.78 Vancouver            Manager
05   Robert               Black                15-JAN-84 08-AUG-98    4334.78 Vancouver            Tester
06   Linda                Green                30-JUL-87 04-JAN-96    5334.78 New York             Tester
07   David                Larry                31-DEC-90 12-FEB-98    6334.78 New York             Manager
08   James                Cat                  17-SEP-96 15-APR-02    7334.78 Vancouver            Tester

8 rows selected.

SQL>
SQL>
SQL> -- the top five salaries
SQL>
SQL> SELECT * FROM
  2  (SELECT id, first_name, salary, DENSE_RANK() OVER(ORDER BY salary desc) toprank
  3  FROM employee)
  4  WHERE toprank <= 5;

ID   FIRST_NAME               SALARY    TOPRANK
---- -------------------- ---------- ----------
08   James                   7334.78          1
07   David                   6334.78          2
06   Linda                   5334.78          3
05   Robert                  4334.78          4
04   Celia                   3334.78          5

SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /

Table dropped.

SQL>
SQL>
SQL>

SELECT *
  FROM (SELECT   ID, first_name, salary
            FROM employee
        ORDER BY salary DESC)
 WHERE ROWNUM <= 5