DB2 Version 9.7 for Linux, UNIX, and Windows

GROUPING aggregate function


>>-GROUPING--(--expression--)----------------------------------><

The schema is SYSIBM.

Used in conjunction with grouping-sets and super-groups, the GROUPING function returns a value that indicates whether or not a row returned in a GROUP BY answer set is a row generated by a grouping set that excludes the column represented by expression.

The argument can be of any type, but must be an item of a GROUP BY clause.

The result of the function is a small integer. It is set to one of the following values:

1: The value of expression in the returned row is a null value, and the row was generated by the super-group. This generated row can be used to provide sub-total values for the GROUP BY expression.
0: The value is other than the above.

Example:

The following query:

   SELECT SALES_DATE, SALES_PERSON,
       SUM(SALES) AS UNITS_SOLD,
       GROUPING(SALES_DATE) AS DATE_GROUP,
       GROUPING(SALES_PERSON) AS SALES_GROUP
     FROM SALES
     GROUP BY CUBE (SALES_DATE, SALES_PERSON)
     ORDER BY SALES_DATE, SALES_PERSON

results in:

SALES_DATE SALES_PERSON    UNITS_SOLD  DATE_GROUP  SALES_GROUP
---------- --------------- ----------- ----------- -----------
12/31/1995 GOUNOT                    1           0           0
12/31/1995 LEE                       6           0           0
12/31/1995 LUCCHESSI                 1           0           0
12/31/1995 -                         8           0           1
03/29/1996 GOUNOT                   11           0           0
03/29/1996 LEE                      12           0           0
03/29/1996 LUCCHESSI                 4           0           0
03/29/1996 -                        27           0           1
03/30/1996 GOUNOT                   21           0           0
03/30/1996 LEE                      21           0           0
03/30/1996 LUCCHESSI                 4           0           0
03/30/1996 -                        46           0           1
03/31/1996 GOUNOT                    3           0           0
03/31/1996 LEE                      27           0           0
03/31/1996 LUCCHESSI                 1           0           0
03/31/1996 -                        31           0           1
04/01/1996 GOUNOT                   14           0           0
04/01/1996 LEE                      25           0           0
04/01/1996 LUCCHESSI                 4           0           0
04/01/1996 -                        43           0           1
-          GOUNOT                   50           1           0
-          LEE                      91           1           0
-          LUCCHESSI                14           1           0
-          -                       155           1           1

An application can recognize a SALES_DATE sub-total row by the fact that the value of DATE_GROUP is 0 and the value of SALES_GROUP is 1. A SALES_PERSON sub-total row can be recognized by the fact that the value of DATE_GROUP is 1 and the value of SALES_GROUP is 0. A grand total row can be recognized by the value 1 for both DATE_GROUP and SALES_GROUP.