SQL Server 2008 + Creating a cross-tab stored procedure - sql

Question

I have two tables that I want to join and create a crosstab table in SQL 2008:
TableA:
Auto_ID | Fiscal_Period | Amount
1 | 01012012 | NULL
1 | 01022012 | 80
1 | 01032012 | NULL
2 | 01012012 | NULL
2 | 01022012 | 10
TABLEB:
Auto_ID | Row_ID | StaticData
1 | 1 | sampledata
2 | 2 | data1
I would like to use cross table to dynamic create the following table structure:
Row_ID | StaticData | FiscalPeriod(01012012) | FiscalPeriod(01022012) | FiscalPeriod(01032012)
1 | sampledata | NULL | 80 | NULL
2 | data1 | NULL | 10 | NULL
My current query joins the tables correctly; however, I am having difficulty transposing the fiscal periods into my header row.
SELECT *
FROM (SELECT
B.Row_Id as RowID, B.StaticData as StaticData, A.Fiscal_Period AS FPPD
FROM TableA A
LEFT JOIN TableB B ON A.Auto_ID = B.Auto_ID)

Answer 1

This is what I would do:
First create some test data:
CREATE TABLE tblA (Auto_ID INT,Fiscal_Period VARCHAR(100),Amount FLOAT)
CREATE TABLE tblB (Auto_ID INT,Row_ID INT,StaticData VARCHAR(100))
INSERT INTO tblA
SELECT 1,'01012012',NULL UNION ALL
SELECT 1,'01022012',80 UNION ALL
SELECT 1,'01032012',NULL UNION ALL
SELECT 2,'01012012',NULL UNION ALL
SELECT 2,'01022012',10
INSERT INTO tblB
SELECT 1,1,'sampledata' UNION ALL
SELECT 2,2,'data1'
Then find the unique columns :
DECLARE #cols VARCHAR(MAX)
;WITH CTE
AS
(
SELECT
ROW_Number() OVER(PARTITION BY tblA.Fiscal_Period ORDER BY tblA.Fiscal_Period) AS RowNbr,
tblA.Fiscal_Period
FROM
tblA AS tblA
)
SELECT
#cols = COALESCE(#cols + ','+QUOTENAME('FiscalPeriod('+Fiscal_Period+')'),
QUOTENAME('FiscalPeriod('+Fiscal_Period+')'))
FROM
CTE
WHERE
CTE.RowNbr=1
Then execute a pivot with dynamic sql:
DECLARE #query NVARCHAR(4000)=
N'SELECT
*
FROM
(
SELECT
tblB.Row_ID,
tblb.StaticData,
''FiscalPeriod(''+tblA.Fiscal_Period+'')'' AS Name,
tblA.Amount
FROM
tblA AS tblA
JOIN tblB AS tblB
ON tblA.Auto_ID=tblB.Auto_ID
) AS p
PIVOT
(
SUM(Amount)
FOR Name IN ('+#cols+')
) AS Pvt'
EXECUTE(#query)
Then in my case I will drop the temp tables:
DROP TABLE tblA
DROP TABLE tblB
I hope this will help you

Answer 2

Since you didn't specify a flavour of database, please mind, that the following is valid only for MySQL!
A cross-tab query is possible only with a very dirty trick, it is only practically feasable in a stored proc.
You start by thinking out some way, to transform a list of fiscal periods into SQL, something like
SELECT
TABLEB.Row_ID,
TABLEB.staticdata
,fp01012012.Amount as fp01012012amount
,fp01022012.Amount as fp01022012amount
,fp01032012.Amount as fp01032012amount
FROM
TABLEB
LEFT JOIN TableA AS fp01012012 ON fp01012012.Auto_ID=TABLEB.Auto_ID AND fp01012012.Fiscal_Period='01012012'
LEFT JOIN TableA AS fp01022012 ON fp01022012.Auto_ID=TABLEB.Auto_ID AND fp01022012.Fiscal_Period='01022012'
LEFT JOIN TableA AS fp01032012 ON fp01032012.Auto_ID=TABLEB.Auto_ID AND fp01032012.Fiscal_Period='01032012'
Which you now have to build as dynamic SQL - this is feasable only in a stored proc.
DELIMITER $$
DROP PROCEDURE IF EXISTS `create_fiscal_data`$$
CREATE PROCEDURE `create_fiscal_data` ()
BEGIN
DECLARE dynfields VARCHAR(10000) DEFAULT 'SELECT TABLEB.Row_ID, TABLEB.staticdata';
DECLARE dynfrom VARCHAR(10000) DEFAULT ' FROM TABLEB';
DECLARE period VARCHAR(10) DEFAULT '';
DECLARE done INT DEFAULT 0;
DECLARE id INT DEFAULT 7;
DECLARE periods CURSOR FOR SELECT DISTINCT Fiscal_Period FROM TableA;
DECLARE CONTINUE HANDLER FOR NOT FOUND SET done=1;
OPEN periods;
cycleperiods: LOOP
FETCH periods INTO period;
IF done=1 THEN LEAVE cycleperiods; END IF;
SET dynfields=CONCAT(dynfields,',`fp',period,'`.Amount AS `fp',period,'amount`');
SET dynfrom=CONCAT(dynfrom,' LEFT JOIN TableA AS `fp',period,'` ON `fp',period,'`.Auto_ID=TABLEB.Auto_ID AND `fp',period,'`.Fiscal_Period="',period,'"');
END LOOP;
CLOSE periods;
SELECT #dynsql:=CONCAT(dynfields,dynfrom) INTO dynfields;
-- Here comes the trick!
PREPARE dynqry FROM #dynsql;
EXECUTE dynqry;
END$$
DELIMITER ;
The trick is, to build the SQL into the variable #dynsql (DECLAREd variables won't work), then prepare and execute it.
Now the query
CALL `create_fiscal_data;`
Will create the output you need.