Example: Remaining Sum - Advanced SQL Engine - Teradata Database

The following query returns the remaining sum of meat sales for all cities. Note there is no PARTITION BY clause in the SUM function, so all cities are included in the remaining sum.

   SELECT city, kind, sales,
   SUM(sales) OVER (ORDER BY city, kind
                    ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING)
   FROM monthly;

The possible results of the preceding SELECT appear in the table below.

city     kind           sales    Remaining Sum(sales)
-------  -------------  -------  --------------------
Omaha    variety pack   25       ?
Omaha    pure pork      125      25
Omaha    pure pork      25       150
Omaha    pure pork      45       175
Chicago  variety pack   55       220
Chicago  variety pack   25       275
Chicago  variety pack   45       300
Chicago  pure pork      50       345

Note that the sort order for the computation is alphabetical by city, and then by kind. The results, however, appear in the reverse order.

The sort order that you specify in the window specification defines the sort order of the rows over which the function is applied; it does not define the ordering of the results. To order the results, use an ORDER BY phrase in the SELECT statement.

For example:

   SELECT city, kind, sales,
   SUM(sales) OVER (ORDER BY city, kind
                    ROWS BETWEEN 1 FOLLOWING AND UNBOUNDED FOLLOWING)
   FROM monthly
   ORDER BY city, kind;

The possible results of the preceding SELECT appear in the table below:

city     kind           sales    Remaining Sum(sales)
-------  -------------  -------  --------------------
Chicago  pure pork      50       345
Chicago  variety pack   55       265
Chicago  variety pack   25       320
Chicago  variety pack   45       220
Omaha    pure pork      25       70
Omaha    pure pork      125      95
Omaha    pure pork      45       25
Omaha    variety pack   25       ?