GROUPING (T-SQL)

Is an aggregate function that causes an additional column to be output with a value of 1 when the row is added by either the CUBE or ROLLUP operator, or 0 when the row is not the result of CUBE or ROLLUP.

Grouping is allowed only in the select list associated with a GROUP BY clause that contains either the CUBE or ROLLUP operator.

Syntax

GROUPING(column_name)

Arguments

column_name

Is a column in a GROUP BY clause to check for CUBE or ROLLUP null values.

Return Types

int

Remarks

Grouping is used to distinguish the null values returned by CUBE and ROLLUP from standard null values. The NULL returned as the result of a CUBE or ROLLUP operation is a special use of NULL. It acts as a column placeholder in the result set and means “all.”

Examples

This example groups royalty and aggregate advance amounts. The GROUPING function is applied to the royalty column.

USE pubs

SELECT royalty, SUM(advance) 'total advance',
    GROUPING(royalty) 'grp'
    FROM titles
    GROUP BY royalty WITH ROLLUP

The result set shows two null values under royalty. The first NULL represents the group of null values from this column in the table. The second NULL is in the summary row added by the ROLLUP operation. The summary row shows the total advance amounts for all royalty groups and is indicated by 1 in the grp column.

Here is the result set:

royalty        total advance               grp

---------      ---------------------    ---

NULL           NULL                     0 

10             57000.0000               0 

12             2275.0000                0 

14             4000.0000                0 

16             7000.0000                0 

24             25125.0000               0 

NULL           95400.0000               1 

See Also