SQL Dynamic Pivot - how to order columns

Question

I'm working on a dynamic pivot query on a table that contains:

• OID - OrderID
• Size - size of the product
• BucketNum - the order that the sizes should go
• quantity - how many ordered

The size column contains different sizes depending upon the OID.

So, using the code found here, I put this together:

DECLARE @listCol VARCHAR(2000)
DECLARE @query VARCHAR(4000)

SELECT  @listCol = STUFF(( SELECT distinct  '], [' + [size]
                           FROM     #t
                         FOR
                           XML PATH('')
                         ), 1, 2, '') + ']'


SET @query = 'SELECT * FROM
      (SELECT OID,  [size], [quantity]
            FROM #t 
            ) src
PIVOT (SUM(quantity) FOR Size
IN (' + @listCol + ')) AS pvt'


EXECUTE ( @query )

This works great except that the column headers (the sizes labels) are not in the order based upon the bucketnum column. The are in the order based upon the sizes.

I've tried the optional Order By after the pivot, but that is not working.

How do I control the order in which the columns appear?

Thank you

Answer 1

You need to fix this:

SELECT  @listCol = STUFF(( SELECT distinct  '], [' + [size]
                           FROM     #t
                         FOR
                           XML PATH('')
                         ), 1, 2, '') + ']'

To return the columns in the right order. You might have to do something like this instead of using DISTINCT:

SELECT [size]
FROM     #t
GROUP BY [size]
ORDER BY MIN(BucketNum)

Answer 2

SELECT @listCol = STUFF(
        (SELECT DISTINCT ',' + QUOTENAME(size) AS [size]
        FROM #t
        ORDER BY [size]
        FOR XML PATH('')

Answer 3

I saw this link just today, which uses a CTE to build the column list (which, presumably, you could order) on the fly without the need for dynamic sql:

http://blog.stevienova.com/2009/07/13/using-ctes-to-create-dynamic-pivot-tables-in-sql-20052008/

Answer 4

I had the same problem and tried the solution suggested above but, probably due to my level of understanding, couldn't get it to work. I found a simple hack was to create a Temp table with the column headers ordered correctly using Order by statements and then pull in that list to the variable that sets the dynamic pivot query column names.

e.g.

SELECT WeekNum INTO #T3 
FROM #T2 
GROUP BY WeekNum 
ORDER BY MIN(WeekNum) 

SELECT @ColumnName1 = ISNULL(@ColumnName1 + ',','') + QuoteName(WeekNum) 
FROM (SELECT WeekNum From #T3) AS WeekNum

Worked a treat.

Hope that helps someone.