Projection/Replication in SQL Query? - sql

Question

My SQL is a bit rusty -- is there a SQL way to project an input table that looks something like this:
Name SlotValue Slots
---- --------- -----
ABC 3 1
ABC 4 2
ABC 6 5
Into a 'projected' result table that looks like this:
Name SlotSum Slot
---- ------- ----
ABC 13 1
ABC 10 2
ABC 6 3
ABC 6 4
ABC 6 5
In other words, the result set should contain a number of rows equal to MAX(Slots), enumerated (Slot) from 1 to MAX(Slots), and Sum for each of these 'slots' should reflect the sum of the SlotValues projected out to the 'Slots' position. for the pathological case:
Name SlotValue Slots
---- --------- -----
ABC 4 3
we should get:
Name SlotSum Slot
---- ------- ----
ABC 4 1
ABC 4 2
ABC 4 3
The summation logic is pretty straightforward -- project each SlotValue out to the number of Slots:
SlotValue SlotValue SlotValue Slot Sum
--------- --------- --------- ---- ---
3 4 6 1 13 (3+4+6)
0 4 6 2 10 (0+4+6)
0 0 6 3 6 (0+0+6)
0 0 6 4 6 (0+0+6)
0 0 6 5 6 (0+0+6)
UPDATE: In the end I used a variant of LOCALGHOST's approach in a stored proc. I was hoping there might be a way to do this without a loop.

Answer 1

I'm not sure you'll be able to do this in a view. You'd have to use a procedure.
You could make ProjectedTable a temporary/variable table in the procedure as well. I'd be really interested to see how you'd get this into a view because you need to dynamically generate a range of numbers.
declare #maxSlot int
set #maxSlot = select max(slots) from SlotTable
truncate ProjectedTable
while #i > 0
begin
insert into ProjectedTable (
SlotSum
,Slot
) values (
(select sum(slotValue) from SlotTable where slots >= #maxSlot)
,#maxSlot
)
set #maxSlot = #maxSlot - 1
end
select SlotSum, Slot from ProjectedTable

Answer 2

Here you go. This will do up to 100 slots in its current form. You can use your imagination to accommodate more.
DECLARE #SLOT TABLE
(
SlotName varchar(25) NOT NULL,
SlotValue int NOT NULL,
Slot int NOT NULL
)
INSERT INTO #SLOT (SlotName, SlotValue, Slot)
SELECT 'ABC', 3, 1
UNION
SELECT 'ABC', 4, 2
UNION
SELECT 'ABC', 6, 5
SELECT
CASE
WHEN SLOT.SlotName IS NOT NULL THEN SLOT.SlotName
ELSE
COALESCE(
(SELECT TOP 1 SL.SlotName FROM #SLOT AS SL WHERE SL.Slot < SLOT_PROJECT.Slot ORDER BY SL.Slot DESC),
(SELECT TOP 1 SL.SlotName FROM #SLOT AS SL WHERE SL.Slot > SLOT_PROJECT.Slot ORDER BY SL.Slot ASC)
)
END AS SlotName,
(
SELECT
SUM(SLOT10.SlotValue)
FROM
#SLOT AS SLOT10
WHERE
SLOT10.Slot >= SLOT_PROJECT.Slot
) AS SlotSum,
SLOT_PROJECT.Slot
FROM
(
SELECT
(TENS.Seq + ONES.Seq) AS Slot
FROM
(
SELECT 1 AS Seq
UNION ALL
SELECT 2
UNION ALL
SELECT 3
UNION ALL
SELECT 4
UNION ALL
SELECT 5
UNION ALL
SELECT 6
UNION ALL
SELECT 7
UNION ALL
SELECT 8
UNION ALL
SELECT 9
) AS ONES
CROSS JOIN
(
SELECT 0 AS Seq
UNION ALL
SELECT 10
UNION ALL
SELECT 20
UNION ALL
SELECT 30
UNION ALL
SELECT 40
UNION ALL
SELECT 50
UNION ALL
SELECT 60
UNION ALL
SELECT 70
UNION ALL
SELECT 80
UNION ALL
SELECT 90
) AS TENS
WHERE
(TENS.Seq + ONES.Seq) <= (SELECT MAX(Slot) FROM #SLOT)
) AS SLOT_PROJECT
LEFT JOIN #SLOT AS SLOT ON
SLOT.Slot = SLOT_PROJECT.Slot