trying to add alias for value generated by Where clause

CREATE TABLE Sales (DayCount smallint, Sales money)
CREATE CLUSTERED INDEX ndx_DayCount ON Sales(DayCount)
go
INSERT Sales VALUES (1,120)
INSERT Sales VALUES (2,60)
INSERT Sales VALUES (3,125)
INSERT Sales VALUES (4,40)

DECLARE @DayCount smallint, @Sales money
SET @DayCount = 5
SET @Sales = 10

WHILE @DayCount < 5000
BEGIN
INSERT Sales VALUES (@DayCount,@Sales)
SET @DayCount = @DayCount + 1
SET @Sales = @Sales + 15
END

polkadot (7/31/2012)

Unless I comment out the alias 'AS RunningTotal' the query fails, but I need an alias for the column the WHERE STATEMENT generates. Will someone please show me how to get an alias for the RunningTotal column?

Both query and DDL are taken from the following website:
http://www.sqlteam.com/article/calculating-running-totals

---QUERY that returns cumulative total by DayCount
SELECT a.DayCount,
a.Sales,
SUM(b.Sales)
FROM Sales a
CROSS JOIN Sales b
WHERE (b.DayCount <= a.DayCount) --AS RunningTotal
GROUP BY a.DayCount,a.Sales
ORDER BY a.DayCount,a.Sales

---DDL

CREATE TABLE Sales (DayCount smallint, Sales money)
CREATE CLUSTERED INDEX ndx_DayCount ON Sales(DayCount)
go
INSERT Sales VALUES (1,120)
INSERT Sales VALUES (2,60)
INSERT Sales VALUES (3,125)
INSERT Sales VALUES (4,40)

DECLARE @DayCount smallint, @Sales money
SET @DayCount = 5
SET @Sales = 10

WHILE @DayCount < 5000
 BEGIN
  INSERT Sales VALUES (@DayCount,@Sales)
  SET @DayCount = @DayCount + 1
  SET @Sales = @Sales + 15
 END

-- A. COALESCE method (9sec for 5K records, 2:30 for 20K)
BEGIN
SELECT [Day],
Sales,
Sales+
COALESCE((SELECT SUM(Sales)
FROM ##Sales b
WHERE b.[Day] < a.[Day]),0) AS [Running Total]
FROM ##Sales a
ORDER BY [Day]
END
GO

-- B. Cross Join method (2sec for 5K records, 0:26 for 20K)
SELECT a.[Day],
a.Sales,
SUM(b.Sales) [Running Total]
FROM ##Sales a
CROSS JOIN ##Sales b
WHERE (b.[Day] <= a.[Day])
GROUP BY a.[Day],a.Sales
ORDER BY a.[Day],a.Sales

-- NOTE: B & C have the same query plan.

-- C. Self Join method; Equal to B (2sec for 5K records, 0:26 for 20K)
SELECT a.[Day],
a.Sales,
SUM(b.Sales) [Running Total]
FROM ##Sales a
JOIN ##Sales b
ON (b.[Day] <= a.[Day])
GROUP BY a.[Day],a.Sales
ORDER BY a.[Day],a.Sales

-- D. Cross Apply/Self-Join method (4 sec for 5K records, 1:09 for 20K)
SELECT [Day],
[Sales],
[Running Total]
FROM ##Sales a
CROSS APPLY
(
SELECT [Running Total] = sum(Sales)
FROM ##Sales
WHERE [Day] <= a.[Day]
) RT
ORDER BY [Day];

-- E. rCTE method - Very fast, (17 sec for 1M rows)
;WITH CTE ([Day], [Sales], [Running Total])
AS
(
SELECT [Day],
[Sales],
[Sales]
FROM ##Sales
WHERE [Day] = 1

UNION ALL

SELECT a.[Day],
a.[Sales],
CTE.[Running Total] + a.[Sales]
FROM CTE
JOIN ##Sales a ON CTE.[Day] + 1 = a.[Day]
)
SELECT * FROM CTE
OPTION (MAXRECURSION 0)
GO

-- F. "Quirky Update" Method (fastest, 12 sec for 1M rows)
DECLARE @PrevDay INT, @RunningTotal MONEY = 0

DECLARE @sales TABLE
(
[Day#] int,
[Sales#] MONEY,
[RunningTotal] MONEY,
PRIMARY KEY([Day#] ASC)
);

INSERT INTO @sales ([Day#],[Sales#])
SELECT * FROM ##Sales;

UPDATE @sales
SET @RunningTotal = RunningTotal = CASE
WHEN [Day] = @PrevDay
THEN @RunningTotal+[Sales#]
ELSE Sales#
END,
@PrevDay = [Day]
FROM ##Sales WITH (TABLOCKX)
OPTION (MAXDOP 1)

SELECT * FROM @sales
GO

-- G. Optimized Cursor, (44sec for 1M rows, 70 seconds without FAST_FORWARD)
BEGIN
DECLARE @Day int, @Sales money
DECLARE @RunningTotal money = 0
DECLARE @SalesTbl_2 TABLE
(
[Day] int,
Sales money,
RunningTotal money,
PRIMARY KEY([Day])
)

DECLARE rt_cursor CURSOR FAST_FORWARD FOR
SELECT [Day], Sales
FROM ##Sales
ORDER BY [Day]

OPEN rt_cursor
FETCH NEXT
FROM rt_cursor
INTO @Day,@Sales

WHILE @@FETCH_STATUS = 0
BEGIN
SET @RunningTotal = @RunningTotal + @Sales

INSERT @SalesTbl_2
VALUES (@Day,@Sales,@RunningTotal)

FETCH NEXT FROM rt_cursor INTO @Day,@Sales
END

CLOSE rt_cursor
DEALLOCATE rt_cursor

SELECT [Day],Sales,RunningTotal FROM @SalesTbl_2
END
GO