SQL query to Transpose columns into rows - tsql

Question

can somebody help with a query for below problem
Return Table
Id Factor monthlyReturns price date
A1 0.2 0.001 2010-01-29
A1 0.2 0.003 2010-02-26
A1 0.2 0.004 2010-03-31
A1 0.2 0.004 2010-04-30
A2 0.1 0.001 2010-01-29
A2 0.1 0.001 2010-02-26
A2 0.1 0.001 2010-03-31
A2 0.1 0.001 2010-04-30
A3 0.3 0.03 2010-01-29
A3 0.3 0.04 2010-02-26
A3 0.3 0.05 2010-03-31
A3 0.3 0.05 2010-04-30
A4 0.4 0.12 2010-01-29
A4 0.4 0.12 2010-02-26
A4 0.4 0.14 2010-03-31
A4 0.4 0.15 2010-04-30
I want to convert this data into following format .Can somebody please suggest a query
A1 A2 A3 A4 Total
31-Jan-10 0.001 0.001 0.03 0.12 0.001*0.2(Factor for A1)+0.001*0.1(Factor forA2)+
0.03*0.3(Factor forA3)+ 0.12*0.4(Factor forA4)
28-Feb-10 0.003 0.001 0.04 0.12 Same as above
31-Mar-10 0.004 0.001 0.05 0.14 Same as above
30-Apr-10 0.004 0.001 0.05 0.15 Same as above
Thanks

Answer 1

below is the query you asked for, notice that you need to change the table name to yours.
a little explanation:
I assumed the Ids are limited to A1,A2,A3,A4. otherwise this will not work and you will need a more complexed solution.
first i created a common table expression of a pivoted table with all the factors grouped by date (assuming that there can not be two factors to the same id on the same date)
then, i join that with a pivoted table that holds all the monthly returns.
note: i used the sum function on the fields A1,A2,.. since i needed to group it by date and the select can only use aggregate function if the column is not in the group by clause.
this does not effect the values since you only have one row for each id on a particular date, but correct me if i'm wrong.
with FactorsByDate(PriceDate,FactorA1,FactorA2,FactorA3,FactorA4)
AS
(
SELECT [price date] AS Date,
SUM([A1]) AS A1, SUM([A2]) AS A2, SUM([A3]) AS A3, SUM([A4]) AS A4
FROM
(SELECT Id, Factor , [price date]
FROM TempTbl) AS SourceTable
PIVOT
(
SUM(Factor)
FOR Id IN ([A1], [A2], [A3], [A4])
) AS PivotTable
group by [price date]
)
SELECT Date,A1,A2,A3,A4, A1*FactorA1 + A2*FactorA2 + A3*FactorA3 + A4*FactorA4 AS Total
FROM
(
SELECT [price date] AS Date,
SUM([A1]) AS A1, SUM([A2]) AS A2, SUM([A3]) AS A3, SUM([A4]) AS A4
FROM
(SELECT Id, monthlyReturns , [price date]
FROM TempTbl) AS SourceTable
PIVOT
(
SUM(monthlyReturns)
FOR Id IN ([A1], [A2], [A3], [A4])
) AS PivotTable
group by [price date]
) AS monthlyReturns
INNER JOIN FactorsByDate ON FactorsByDate.PriceDate = monthlyReturns.Date