Analytical Functions Oracle PLSQL

SQL> -- create demo table
SQL> create table Employee(
  2    empno              Number(3)  NOT NULL, -- Employee ID
  3    ename              VARCHAR2(10 BYTE),   -- Employee Name
  4    hireDate          DATE,                -- Date Employee Hired
  5    orig_salary        Number(8,2),         -- Orignal Salary
  6    curr_salary        Number(8,2),         -- Current Salary
  7    region             VARCHAR2(1 BYTE)     -- Region where employeed
  8  )
  9  /
Table created.
SQL>
SQL>
SQL> -- prepare data for employee table
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(122,'Alison',to_date('19960321','YYYYMMDD'), 45000,       48000,       'E')
  3  /
1 row created.
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(123, 'James',to_date('19781212','YYYYMMDD'), 23000,       32000,       'W')
  3  /
1 row created.
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(104,'Celia',to_date('19821024','YYYYMMDD'), 53000,       58000,        'E')
  3  /
1 row created.
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(105,'Robert',to_date('19840115','YYYYMMDD'), 31000,      36000,        'W')
  3  /
1 row created.
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(116,'Linda', to_date('19870730','YYYYMMDD'), 43000,       53000,       'E')
  3  /
1 row created.
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(117,'David', to_date('19901231','YYYYMMDD'), 78000,       85000,       'W')
  3  /
1 row created.
SQL> insert into Employee(empno,  ename,  hireDate,                       orig_salary, curr_salary, region)
  2                values(108,'Jode',  to_date('19960917','YYYYMMDD'), 21000,       29000,       'E')
  3  /
1 row created.
SQL>
SQL>
SQL> select * from employee;
     EMPNO ENAME      HIREDATE  ORIG_SALARY CURR_SALARY R
---------- ---------- --------- ----------- ----------- -
       122 Alison     21-MAR-96       45000       48000 E
       123 James      12-DEC-78       23000       32000 W
       104 Celia      24-OCT-82       53000       58000 E
       105 Robert     15-JAN-84       31000       36000 W
       116 Linda      30-JUL-87       43000       53000 E
       117 David      31-DEC-90       78000       85000 W
       108 Jode       17-SEP-96       21000       29000 E
7 rows selected.
SQL>
SQL> -- See the difference between a person's salary and the average for his or her region
SQL>
SQL>
SQL>
SQL> SELECT empno, ename, region, curr_salary,
  2    orig_salary,
  3    ROUND(AVG(orig_salary) OVER(PARTITION BY region))
  4        "Avg-group",
  5    ROUND(orig_salary - AVG(orig_salary) OVER(PARTITION
  6        BY region)) "Diff."
  7  FROM employee
  8  ORDER BY region, ename;
     EMPNO ENAME      R CURR_SALARY ORIG_SALARY  Avg-group      Diff.
---------- ---------- - ----------- ----------- ---------- ----------
       122 Alison     E       48000       45000      40500       4500
       104 Celia      E       58000       53000      40500      12500
       108 Jode       E       29000       21000      40500     -19500
       116 Linda      E       53000       43000      40500       2500
       117 David      W       85000       78000      44000      34000
       123 James      W       32000       23000      44000     -21000
       105 Robert     W       36000       31000      44000     -13000
7 rows selected.
SQL>
SQL>
SQL> -- clean the table
SQL> drop table Employee
  2  /
Table dropped.
SQL>
SQL>
SQL>