get cross tabulated report according to data available - pivot - sql

Question

I want to pivot and turn an existing table and generate a report(cross tabulated). You see vals column is determined by unique combination of date_a and date_e columns. I don't know how to do this.

Answer 1

Something like this:
Test data
CREATE TABLE #tbl(date_a DATE,date_e DATE, vals FLOAT)
INSERT INTO #tbl
VALUES
('2/29/2012','1/1/2013',28.47),
('2/29/2012','2/1/2013',27.42),
('2/29/2012','3/1/2013',24.36),
('3/1/2012','1/1/2013',28.5),
('3/1/2012','2/1/2013',27.35),
('3/1/2012','3/1/2013',24.39),
('3/6/2012','1/1/2013',27.75),
('3/6/2012','2/1/2013',26.63),
('3/6/2012','3/1/2013',23.66)
Query
SELECT
*
FROM
(
SELECT
tbl.date_a,
tbl.date_e,
vals
FROM
#tbl AS tbl
) AS SourceTable
PIVOT
(
SUM(vals)
FOR date_e IN ([1/1/2013],[2/1/2013],[3/1/2013])
) AS pvt
DROP TABLE #tbl
EDIT
If you do not know how many columns there is then you need to do a dynamic pivot. Like this:
The unique columns
DECLARE #cols VARCHAR(MAX)
;WITH CTE
AS
(
SELECT
ROW_NUMBER() OVER(PARTITION BY date_e ORDER BY date_e) AS RowNbr,
tbl.*
FROM
#tbl AS tbl
)
SELECT #cols=STUFF
(
(
SELECT
',' +QUOTENAME(date_e)
FROM
CTE
WHERE
CTE.RowNbr=1
FOR XML PATH('')
)
,1,1,'')
Dynamic pivot
DECLARE #query NVARCHAR(4000)=
N'SELECT
*
FROM
(
SELECT
tbl.date_a,
tbl.date_e,
vals
FROM
#tbl AS tbl
) AS SourceTable
PIVOT
(
SUM(vals)
FOR date_e IN ('+#cols+')
) AS pvt'
EXECUTE(#query)