SELECT *
FROM(
SELECT y.TotalSizeGB,
CASE
WHEN y.AnotherGrp%2=0 AND y.PseudoGrpNumber=0 THEN 2
WHEN y.AnotherGrp%2=0 AND y.PseudoGrpNumber=1 THEN 1
WHEN y.AnotherGrp%2=0 AND y.PseudoGrpNumber=2 THEN 0
ELSE y.PseudoGrpNumber
END GrpNumber
FROM(
SELECT
x.ServerName,
x.TotalSizeGB,
(2+ROW_NUMBER() OVER(ORDER BY x.TotalSizeGB DESC))%3 PseudoGrpNumber,
(2+ROW_NUMBER() OVER(ORDER BY x.TotalSizeGB DESC))/3 AnotherGrp,
ROW_NUMBER() OVER(ORDER BY x.TotalSizeGB DESC) RowNum
FROM @Servers x
)y
)z
PIVOT( SUM(z.TotalSizeGB) FOR z.GrpNumber IN([0],[1],[2]) ) pvt;
Risultati:
0 1 2
------- ------- -------
2048.02 1925.80 2037.14
Alcune spiegazioni:
L'idea è di ordinare i dati decrescente su TotalSizeGB colonna. Quindi ogni 3 righe sequenziali vengono raggruppate insieme (colonna AnotherGrp ) prima in DESC ordine e poi in ASC ordine (colonna PseudoGroNumber e GrpNumber ). Se viene eseguito SELECT * FROM () y tabella derivata, i risultati saranno:
ServerName TotalSizeGB PseudoGrpNumber AnotherGrp GrpNumber RowNum
---------- ------------ --------------- ---------- --------- ------
Server10 1023.35 0 1 0 1
Server9 901.23 1 1 1 2
Server8 890.12 2 1 2 3
Server7 789.01 0 2 2 4
Server6 678.90 1 2 1 5
Server5 567.89 2 2 0 6
Server4 456.78 0 3 0 7
Server3 345.67 1 3 1 8
Server2 234.56 2 3 2 9
Server1 123.45 0 4 2 10
