GROUPING() with a Single Column in a ROLLUP : GROUPING « Analytical Functions « Oracle PL/SQL Tutorial






  1. The GROUPING() function accepts a column and returns 0 or 1.
  2. GROUPING() returns 1 when the column value is null, and returns 0 when the column value is non-null.
  3. GROUPING() is only used in queries that use ROLLUP or CUBE.
  4. GROUPING() is useful when you want to display a value when a null would otherwise be returned.
SQL>
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('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'), 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('19900315','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('19990421','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('19980808','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('19960104','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('19980212','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('20020415','YYYYMMDD'), 1232.78, NULL, '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            Tester

8 rows selected.

SQL>
SQL>
SQL>
SQL> SELECT city, SUM(salary)
  2  FROM employee
  3  GROUP BY ROLLUP(city);

CITY       SUM(SALARY)
---------- -----------
New York      12220.56
Toronto        1234.56
Vancouver     17886.12
               1232.78
              32574.02

SQL>
SQL> SELECT GROUPING(city), city, SUM(salary)
  2  FROM employee
  3  GROUP BY ROLLUP(city);

GROUPING(CITY) CITY       SUM(SALARY)
-------------- ---------- -----------
             0 New York      12220.56
             0 Toronto        1234.56
             0 Vancouver     17886.12
             0                1232.78
             1               32574.02

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

Table dropped.

SQL>
SQL>








16.13.GROUPING
16.13.1.GROUPING() with a Single Column in a ROLLUP
16.13.2.Using DECODE() to Convert the Returned Value from GROUPING()
16.13.3.Using DECODE() and GROUPING() to Convert Multiple Column Values
16.13.4.Using GROUPING() with CUBE
16.13.5.Using the GROUPING SETS Clause
16.13.6.Computing the GROUPING Bit Vector
16.13.7.Using the GROUP_ID() Function
16.13.8.Eliminate duplicate rows using a HAVING clause that only allows rows whose GROUP_ID() is 0
16.13.9.Grouping with Rollup and Cube
16.13.10.Use GROUPING(x) function in a DECODE or CASE to enhance the result
16.13.11.Use the BREAK reporting tool to space the display conveniently
16.13.12.Getting Values and Subtotals in One Go with GROUPING SETS