GROUPING Function Example | Teradata Vantage - Example: Viewing Sales Summaries by County and by City - Analytics Database - Teradata Vantage

Suppose you have the following data in the sales_view table.

To look at sales summaries by county and by city, use the following SELECT statement:

   SELECT county, city, sum(margin) 
   FROM sale_view
   GROUP BY GROUPING SETS ((county),(city));

The query reports the following data:

   County       City        Sum(margin)
   -----------  ----------  -----------
   Los Angeles  ?                 38700
   San Diego    ?                 19500
   ?            Long Beach        24300
   ?            San Diego         19500
   ?            Avalon            14400

Notice that in this example, a null represents all values for a column because the column was excluded from the grouping set represented.

To distinguish between rows with nulls in actual data from rows with nulls generated from grouping sets, use the GROUPING function:

   SELECT county, city, sum(margin), 
          GROUPING(county) AS County_Grouping, 
          GROUPING(city) AS City_Grouping
   FROM sale_view
   GROUP BY GROUPING SETS ((county),(city));

The results are:

   County      City       Sum(margin) County_Grouping City_Grouping
   ----------- ---------- ----------- --------------- -------------
   Los Angeles ?                38700               0             1
   San Diego   ?                19500               0             1
   ?           Long Beach       24300               1             0
   ?           San Diego        19500               1             0
   ?           Avalon           14400               1             0
   

You can also use GROUPING to replace the nulls that appear in a result row because the extended grouping specification aggregated over a column and excluded it from the particular grouping. For example:

   SELECT CASE 
            WHEN GROUPING(county) = 1
            THEN '-All Counties-'
            ELSE county
          END AS County,
          CASE 
            WHEN GROUPING(city) = 1
            THEN '-All Cities-'
            ELSE city
          END AS City,
          SUM(margin) 
   FROM sale_view
   GROUP BY GROUPING SETS (county,city);

The query reports the following data:

   County          City          Sum(margin)
   --------------  ------------  -----------
   Los Angeles     -All Cities-        38700
   San Diego       -All Cities-        19500
   -All Counties-  Long Beach          24300
   -All Counties-  San Diego           19500
   -All Counties-  Avalon              14400