Benutzerdefinierte Berechnung für den Betrag

Hier ist ein alternativer Ansatz, der LAG() erfordert, das von SQL 2012 verfügbar ist, aber beachten Sie, dass die Beispieldaten nicht „28 verschiedene Tage“ vor jedem Datum enthalten. Auch ist der tatsächlich verwendete Datentyp nicht bekannt (date/smalldatetime/datetime/datetime2) und es ist auch nicht bekannt, ob das Abschneiden der Zeit vom Datum erforderlich ist. Mit einigen Vorbehalten erstellt dieser Ansatz also eine Reihe von Datumsbereichen für die 28 unterschiedlichen Daten (aber liefern die Daten diese nicht, dann sind es 28 verstrichene Tage). Hier ist eine sqlfiddle-Demo

PostgreSQL 9.3-Schema-Setup :(da SQL Server nicht bei sqlfiddle arbeitet)

CREATE TABLE Table1
    (theDate timestamp, Value int, promo int, item int)
;

INSERT INTO Table1
    (theDate, Value, promo, item)
VALUES
    ('2011-01-01 00:00:00', 626, 0, 1230),
    ('2011-01-02 00:00:00', 231, 1, 1230),
    ('2011-01-03 00:00:00', 572, 1, 1230),
    ('2011-01-04 00:00:00', 775, 1, 1230),
    ('2011-01-05 00:00:00', 660, 1, 1230),
    ('2011-01-06 00:00:00', 662, 1, 1230),
    ('2011-01-07 00:00:00', 541, 1, 1230),
    ('2011-01-08 00:00:00', 849, 1, 1230),
    ('2011-01-09 00:00:00', 632, 1, 1230),
    ('2011-01-10 00:00:00', 906, 1, 1230),
    ('2011-01-11 00:00:00', 961, 1, 1230),
    ('2011-01-12 00:00:00', 361, 0, 1230),
    ('2012-01-01 00:00:00', 461, 0, 1230),
    ('2012-01-02 00:00:00', 928, 1, 1230),
    ('2012-01-03 00:00:00', 855, 0, 1230),
    ('2012-01-04 00:00:00', 605, 0, 1230),
    ('2012-01-05 00:00:00', 83, 0, 1230),
    ('2012-01-06 00:00:00', 44, 0, 1230),
    ('2012-01-07 00:00:00', 382, 0, 1230),
    ('2012-01-08 00:00:00', 862, 0, 1230),
    ('2012-01-09 00:00:00', 549, 0, 1230),
    ('2012-01-10 00:00:00', 632, 0, 1230),
    ('2012-01-11 00:00:00', 2, 0, 1230),
    ('2012-01-12 00:00:00', 26, 0, 1230)
;

Abfrage 1 :

select
      t1.item
    , ranges.theStart
    , ranges.theEnd
    , sum(t1.value)
    , sum(t1.value) / 28 avg
from (
      select
            coalesce(lag(theDay,28) over(order by theDay) , theDay - INTERVAL '28 DAYS') as theStart
          , theDay as theEnd
      from (
            select distinct cast(thedate as date) theDay from Table1
            ) days
      ) ranges
inner join table1 t1 on theDate between ranges.theStart and ranges.theEnd
group by
      t1.item
    , ranges.theStart
    , ranges.theEnd

Ergebnisse :

| item |                   thestart |                    theend |  sum | avg |
|------|----------------------------|---------------------------|------|-----|
| 1230 | December, 04 2010 00:00:00 | January, 01 2011 00:00:00 |  626 |  22 |
| 1230 | December, 05 2010 00:00:00 | January, 02 2011 00:00:00 |  857 |  30 |
| 1230 | December, 06 2010 00:00:00 | January, 03 2011 00:00:00 | 1429 |  51 |
| 1230 | December, 07 2010 00:00:00 | January, 04 2011 00:00:00 | 2204 |  78 |
| 1230 | December, 08 2010 00:00:00 | January, 05 2011 00:00:00 | 2864 | 102 |
| 1230 | December, 09 2010 00:00:00 | January, 06 2011 00:00:00 | 3526 | 125 |
| 1230 | December, 10 2010 00:00:00 | January, 07 2011 00:00:00 | 4067 | 145 |
| 1230 | December, 11 2010 00:00:00 | January, 08 2011 00:00:00 | 4916 | 175 |
| 1230 | December, 12 2010 00:00:00 | January, 09 2011 00:00:00 | 5548 | 198 |
| 1230 | December, 13 2010 00:00:00 | January, 10 2011 00:00:00 | 6454 | 230 |
| 1230 | December, 14 2010 00:00:00 | January, 11 2011 00:00:00 | 7415 | 264 |
| 1230 | December, 15 2010 00:00:00 | January, 12 2011 00:00:00 | 7776 | 277 |
| 1230 | December, 04 2011 00:00:00 | January, 01 2012 00:00:00 |  461 |  16 |
| 1230 | December, 05 2011 00:00:00 | January, 02 2012 00:00:00 | 1389 |  49 |
| 1230 | December, 06 2011 00:00:00 | January, 03 2012 00:00:00 | 2244 |  80 |
| 1230 | December, 07 2011 00:00:00 | January, 04 2012 00:00:00 | 2849 | 101 |
| 1230 | December, 08 2011 00:00:00 | January, 05 2012 00:00:00 | 2932 | 104 |
| 1230 | December, 09 2011 00:00:00 | January, 06 2012 00:00:00 | 2976 | 106 |
| 1230 | December, 10 2011 00:00:00 | January, 07 2012 00:00:00 | 3358 | 119 |
| 1230 | December, 11 2011 00:00:00 | January, 08 2012 00:00:00 | 4220 | 150 |
| 1230 | December, 12 2011 00:00:00 | January, 09 2012 00:00:00 | 4769 | 170 |
| 1230 | December, 13 2011 00:00:00 | January, 10 2012 00:00:00 | 5401 | 192 |
| 1230 | December, 14 2011 00:00:00 | January, 11 2012 00:00:00 | 5403 | 192 |
| 1230 | December, 15 2011 00:00:00 | January, 12 2012 00:00:00 | 5429 | 193 |

Hinweis:Für SQL Server

• statt theDay - INTERVAL '28 DAYS' Verwenden Sie dateadd(day,-28,theDay)