Dynamic PIVOT on multiple columns

In this blog post I want to discuss a problem I encounter frequently in SQL related forums – how to perform dynamic PIVOT involving multiple columns using pure T-SQL solution. In SQL Server Reporting Services this functionality can be easily achieved using Matrix template.
With the introduction of PIVOT operator in SQL 2005, it became very easy to write queries that transform rows into columns. There are numerous articles on the Web as how to perform PIVOT and even dynamic PIVOT. However, most of these articles explain how to perform such queries for just one column. I want to expand the transformation for multiple columns.
The idea of a solution is quite simple – you need to generate the SQL dynamically. Since we want to use pivot on multiple columns, we need to use CASE based pivot.
You need to keep in mind, that resulting query should have less than 1024 columns. You may build the check for number of columns into the query.
Now, every time I need to create a dynamic query, I need to know what is the final query I am going to arrive to. Having the idea in mind and printing the SQL command until I got it right helps to create the working query.
Let’s consider the first example based on the AdventureWorks SalesOrderHeader table.
This code creates the table we’re going to transform – it gives us summary of orders and total due per each quarter:

T-SQL

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USE AdventureWorks   SELECT   DATEPART(quarter,OrderDate) AS [Quarter],          DATEPART(YEAR,OrderDate)    AS [Year],          COUNT(SalesOrderID)         AS [Orders Count],          SUM(TotalDue)               AS [Total Due] INTO     #SalesSummary FROM     Sales.SalesOrderHeader GROUP BY DATEPART(quarter,OrderDate),          DATEPART(YEAR,OrderDate)   SELECT   * FROM     #SalesSummary ORDER BY [Year],          [Quarter]

The #SalesSummary table lists count of orders and total due for each quarter and year.

Quarterly Orders Summary

Quarter	Year	Orders Count	Total Due
3	2001	621	$5,850,932.9483
4	2001	758	$8,476,619.278
1	2002	741	$7,379,686.3091
2	2002	825	$8,210,285.1655
3	2002	1054	$13,458,206.13
4	2002	1072	$10,827,327.4904
1	2003	1091	$8,550,831.8702
2	2003	1260	$10,749,269.374
3	2003	4152	$18,220,131.5285
4	2003	5940	$16,787,382.3141
1	2004	6087	$14,170,982.5455
2	2004	6888	$17,969,750.9487
3	2004	976	$56,178.9223

Now, suppose we want to see these results horizontally. The following dynamic SQL produces the desired output:

T-SQL

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DECLARE  @SQL  NVARCHAR(MAX),          @Cols NVARCHAR(MAX)           SELECT @Cols = STUFF((select ', SUM(CASE WHEN [Quarter]=' + CAST([Quarter] as varchar(3)) + ' AND [Year] = ' + CAST([Year] as char(4)) + ' THEN [Orders Count] ELSE 0 END) AS [' + CAST([Year] as char(4)) + '-' + CAST([Quarter] as varchar(3)) + ' Orders], SUM(CASE WHEN [Quarter]=' + CAST([Quarter] as varchar(3)) + ' AND [Year] = ' + CAST([Year] as char(4)) + ' THEN [Total Due] ELSE 0 END) AS [' + CAST([Year] as char(4)) + '-' + CAST([Quarter] as varchar(3)) + ' Sales]' FROM #SalesSummary ORDER BY [Year],[Quarter] FOR XML PATH(''),type).value('.','varchar(max)'),1,2,'')   SET @SQL = 'SELECT ' + @Cols + '  FROM #SalesSummary'   --print @SQL EXECUTE( @SQL)

It produces the transformed result (I show only few first columns):

Transformed result

2001-3 Orders	2001-3 Sales	2001-4 Orders	2001-4 Sales	2002-1 Orders	2002-1 Sales	2002-2 Orders	2002-2 Sales
621	$5,850,932.9483	758	$8,476,619.278	741	$7,379,686.3091	825	$8,210,285.1655

You may want to un-comment PRINT @SQL statement if you want to see the generated command. I used XML PATH to concatenate rows into a string based on this blog post by Brad Schulz Making a list and checking it twice.
Another interesting problem was presented in this MSDN Transact-SQL forum thread:
For the claims table that has many integer columns, transform rows into columns. I demonstrate just the solution with the table creation script:

T-SQL

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USE tempdb   IF OBJECT_ID('Claims','U') IS NOT NULL   DROP TABLE Claims   GO   CREATE TABLE Claims (   Claim  INT,   HCPC   INT,   [mod]  INT,   charge INT,   paid   INT,   Qty    INT)   INSERT INTO Claims SELECT 12345,        99245,        90,        20,        10,        1 UNION ALL SELECT 12345,        99112,        NULL,        30,        20,        1 UNION ALL SELECT 12345,        99111,        80,        50,        25,        2 UNION ALL SELECT 11112,        99911,        60,        50,        20,        1 UNION ALL SELECT 12222,        99454,        NULL,        50,        20,        1   SELECT * FROM Claims

The output is:

Claims table

Claim	HCPC	mod	Charge	Paid	Qty
12345	99245	90	20	10	1
12345	99112	NULL	30	20	1
12345	99111	80	50	25	2
11112	99911	60	50	20	1
12222	99454	NULL	50	20	1

And the following code transforms the result (as you see, I am using a loop and ROW_NUMBER() approach):

T-SQL

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DECLARE  @SQL     NVARCHAR(MAX),          @Loop    INT,          @MaxRows INT   SET @Sql = ''   SELECT @MaxRows = MAX(MaxRow) FROM   (SELECT   COUNT(* ) AS MaxRow,                  Claim         FROM     Claims         GROUP BY Claim) X   SET @Loop = 1   WHILE @Loop <= @MaxRows   BEGIN     SELECT @SQL = @SQL + ',     SUM(CASE WHEN Row = ' + CAST(@Loop AS VARCHAR(10)) + ' THEN ' + QUOTENAME(Column_Name) + ' END) AS [' + COLUMN_NAME + CAST(@Loop AS VARCHAR(10)) + ']'     FROM   INFORMATION_SCHEMA.COLUMNS     WHERE  TABLE_Name = 'Claims'            AND COLUMN_NAME NOT IN ('Row','Claim')           SET @Loop = @Loop + 1   END   --PRINT @SQL SET @SQL = 'SELECT Claim' + @SQL + ' FROM (select *,          row_number() over (partition by Claim ORDER BY Claim) as Row         FROM Claims) X GROUP BY Claim '   PRINT @SQL   EXECUTE( @SQL)

Transformed Output

Claim	HCPC1	mod1	Charge1	Paid1	Qty1	HCPC2	mod2	Charge2	Paid2	Qty2	HCPC3	mod3	Charge3	Paid3	Qty3
11112	99911	60	50	20	1	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
12222	99454	NULL	50	20	1	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL
12345	99245	90	20	10	1	99112	NULL	30	20	1	99111	80	50	25	2

I’ll post another recent problem found in the following MSDN thread Basic Crosstab Query

T-SQL

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SET NOCOUNT ON; GO USE tempdb; GO CREATE TABLE #T ( StoreID char(5) NOT NULL, CriteriaNo int NOT NULL, Result int NOT NULL, Position int NOT NULL, PRIMARY KEY (StoreID, CriteriaNo) ); GO INSERT INTO #T(StoreID, CriteriaNo, Result, Position) SELECT '0001', 9, 10, 1 UNION ALL SELECT '0002', 9, 12, 2 UNION ALL SELECT '0001', 10, 5, 1 UNION ALL SELECT '0002', 10, 6, 2; GO -- dynamic DECLARE @sql nvarchar(MAX), @Cols nvarchar(max);   SELECT @Cols = (select ', ' + 'MAX(case when CriteriaNo = ' + CONVERT(varchar(20), CriteriaNo) + ' then Result else 0 end) AS CriteriaNo' + CONVERT(varchar(20), CriteriaNo) + ', MAX(case when CriteriaNo = ' + CONVERT(varchar(20), CriteriaNo) + ' then Position else 0 end) AS CriteriaPosition' + CONVERT(varchar(20), CriteriaNo) from (select distinct CriteriaNo from #T) X ORDER By CriteriaNo FOR XML PATH(''))   SET @sql = 'SELECT StoreID' + @Cols + ', SUM(Result) as PerformancePrint FROM #T GROUP BY StoreID'   EXECUTE(@sql)

See also my TechNet WiKi article on this same topic with more code samples
T-SQL: Dynamic Pivot on Multiple Columns
*** Remember, if you have a SQL related question, try our Microsoft SQL Server Programming forum or our Microsoft SQL Server Admin forum

source : http://blogs.lessthandot.com/index.php/datamgmt/datadesign/dynamic-pivot-on-multiple-columns/