Use SUM for windowing : Window Functions « Analytical Functions « Oracle PL/SQL Tutorial






SQL>
SQL>
SQL>
SQL> -- create demo table
SQL> create table Employee(
  2    ID                 VARCHAR2(4 BYTE)         NOT NULL,
  3    First_Name         VARCHAR2(10 BYTE),
  4    Last_Name          VARCHAR2(10 BYTE),
  5    Start_Date         DATE,
  6    End_Date           DATE,
  7    Salary             Number(8,2),
  8    City               VARCHAR2(10 BYTE),
  9    Description        VARCHAR2(15 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('20060
725','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('19860
221','YYYYMMDD'), 6661.78, '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('19900
315','YYYYMMDD'), 6544.78, '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('19990
421','YYYYMMDD'), 2344.78, '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('19980
808','YYYYMMDD'), 2334.78, '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('19960
104','YYYYMMDD'), 4322.78,'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('19980
212','YYYYMMDD'), 7897.78,'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('20020
415','YYYYMMDD'), 1232.78,'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    6661.78 Vancouver  Tester
03   James      Smith      12-DEC-78 15-MAR-90    6544.78 Vancouver  Tester
04   Celia      Rice       24-OCT-82 21-APR-99    2344.78 Vancouver  Manager
05   Robert     Black      15-JAN-84 08-AUG-98    2334.78 Vancouver  Tester
06   Linda      Green      30-JUL-87 04-JAN-96    4322.78 New York   Tester
07   David      Larry      31-DEC-90 12-FEB-98    7897.78 New York   Manager
08   James      Cat        17-SEP-96 15-APR-02    1232.78 Vancouver  Tester

8 rows selected.

SQL>
SQL>
SQL>
SQL> COLUMN ma FORMAT 999999.9999
SQL> COLUMN sum LIKE ma
SQL> COLUMN "sum/3" LIKE ma
SQL> SELECT id, salary,
  2    AVG(salary) OVER(ORDER BY id
  3      ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) ma,
  4    SUM(salary) OVER(ORDER BY id
  5      ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) sum,
  6    (SUM(salary) OVER(ORDER BY id
  7      ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING))/3 "Sum/3"
  8  FROM employee
  9  ORDER BY id;

ID       SALARY           MA          SUM        Sum/3
---- ---------- ------------ ------------ ------------
01      1234.56    3948.1700    7896.3400    2632.1133
02      6661.78    4813.7067   14441.1200    4813.7067
03      6544.78    5183.7800   15551.3400    5183.7800
04      2344.78    3741.4467   11224.3400    3741.4467
05      2334.78    3000.7800    9002.3400    3000.7800
06      4322.78    4851.7800   14555.3400    4851.7800
07      7897.78    4484.4467   13453.3400    4484.4467
08      1232.78    4565.2800    9130.5600    3043.5200

8 rows selected.

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

Table dropped.

SQL>
SQL>








16.29.Window Functions
16.29.1.Using the Window Functions
16.29.2.Performing a Cumulative Sum
16.29.3.Use ROWS UNBOUNDED PRECEDING to implicitly indicate the end of the window is the current row
16.29.4.Performing a Moving Average
16.29.5.Performing a Centered Average
16.29.6.Moving average
16.29.7.Row-ordering is done first and then the moving average
16.29.8.Use SUM for windowing
16.29.9.Use the COUNT aggregate analytical function to show how many rows are included in each window
16.29.10.An Expanded Example of a Physical Window
16.29.11.Displaying which rows are used in the moving average calculations with two other analytical functions: FIRST_ VALUE and LAST_VALUE.