Challenge with Pivoting data

Question

Hi Everyone,
I have an interesting challenge which involves extracting data from two related databases, and pivoting part of the data from the second.
Where I work we use SAP Business One (ERP) in concert with Accellos (WMS). Within our Warehouses we store items in many bin locations. Bin locations; items in those locations, along with quantities, etc are stored in the Accellos database. Master data related
to the items themselves, such as the item cost, preferred supplier, etc is stored in SAP Business One.
Whilst I have been able to create reports which successfully bridge both SAP & Accellos, such as that shown below, I have not been able to present the data output in an ideal format.
As can be seen above given a single item code (e.g.: DR1124) there are many bin labels (and corresponding quantities) returned.
I would like to show the bin labels 'horizontally' in the fashion illustrated below -
I believe that using a Pivot is pivotal (excuse the pun!) to success in my endeavour, and due to this I have studied up on Pivots, both the Static type (which I am now comfortable with) and the Dynamic type (which I am still getting 'my head around').
However there are a couple of challenges related to my specific pivot.
The maximum number of Bins (and correspondingly Bin Labels) per Item change
There are over 10K Bin Labels
I have written a basic Dynamic Pivot which shows all Bin Labels horizontally, like so...
DECLARE @SQL nvarchar(max), @Columns nvarchar(max)
SELECT @Columns =
COALESCE(@Columns + ', ', '') + QUOTENAME(BINLABEL)
FROM
SELECT DISTINCT
BINLABEL
FROM A1Warehouse..BINLOCAT
) AS B
ORDER BY B.BINLABEL
SET @SQL = '
WITH PivotData AS
SELECT
BINLABEL
, PRODUCT
, QUANTITY
FROM A1Warehouse..BINLOCAT
SELECT
PRODUCT,
'+ @Columns +'
FROM PivotData
PIVOT
SUM(QUANTITY)
FOR BINLABEL
IN('+ @Columns +')
) AS PivotResult'
EXEC(@SQL)
The above technique gives me over 10K columns because there are that many Bin Labels in total.
It occurred to me that I would need to count the maximum number of Bin Labels for the Item that had the most Bin Labels, and that this number would then need to be used to set the maximum number of columns.
DECLARE @maxBins int
DECLARE @loopCount int = 1
SET @maxBins = (SELECT MAX([# of Bins]) AS 'Max Bins'
FROM
SELECT
COUNT(BINLABEL) '# of Bins'
FROM A1Warehouse..BINLOCAT
GROUP BY PRODUCT
) AS T0)
PRINT @maxBins
At this point in time one item occupies a total of 26 bin labels / locations. Every other item occupies less than 26 bin labels / locations, so I now know that I need to number my vertical columns as 'Bin 1', 'Bin 2', 'Bin 3', 'Bin...', 'Bin 26'.
This is where the fun starts, I don't exactly need a Dynamic Pivot, but neither is a Static Pivot up to the task (at least not as best I can tell).
Here is the Static Pivot query that I have written -
DECLARE @fromDate DATE = DATEADD(YY, -1, GETDATE())
DECLARE @toDate DATE = GETDATE()
DECLARE @maxBins int
DECLARE @loopCount int = 1
SET @maxBins = (SELECT MAX([# of Bins]) AS 'Max Bins'
FROM
SELECT
COUNT(BINLABEL) '# of Bins'
FROM A1Warehouse..BINLOCAT
GROUP BY PRODUCT
) AS T0)
PRINT @maxBins
SELECT *
FROM
SELECT
Tx.[Item Code]
, Tx.Description
, SUM(Tx.[Sales (last 12 Months)]) AS 'Sales (last 12 Months)'
, ISNULL(Tx.[Supplier Code], '') AS 'Supplier Code'
, ISNULL(Tx.[Supplier Name], '') AS 'Supplier Name'
, Tx.OnOrder
, Tx.IsCommited
, Tx.OnHand
, ISNULL(Tx.BINLABEL, '') AS 'Binlabel'
, ISNULL(CAST(Tx.QUANTITY AS nvarchar), '') AS 'Quantity'
FROM
SELECT
T0.ItemCode AS 'Item Code'
, T0.Dscription AS 'Description'
, SUM(T0.Quantity) AS 'Sales (last 12 Months)'
, T3.CardCode AS 'Supplier Code'
, T3.CardName AS 'Supplier Name'
, T2.OnOrder
, T2.IsCommited
, T2.OnHand
, T4.BINLABEL
, T4.QUANTITY
FROM INV1 T0
INNER JOIN OINV T1 ON T1.DocEntry = T0.DocEntry AND T1.CANCELED = 'N'
INNER JOIN OITM T2 ON T2.ItemCode = T0.ItemCode
LEFT JOIN OCRD T3 ON T3.CardCode = T2.CardCode
LEFT JOIN A1Warehouse..BINLOCAT T4 ON T4.PRODUCT = T0.ItemCode collate SQL_Latin1_General_CP850_CI_AS
WHERE T1.DocDate >= @fromDate AND T1.DocDate <= @toDate
GROUP BY T0.ItemCode, T0.Dscription, T3.CardCode, T3.CardName, T2.OnOrder, T2.IsCommited, T2.OnHand, T4.BINLABEL, T4.QUANTITY
UNION ALL
SELECT
T0.ItemCode AS 'Item Code'
, T0.Dscription AS 'Description'
, -SUM(T0.Quantity) AS 'Sales (last 12 Months)'
, T3.CardCode AS 'Supplier Code'
, T3.CardName AS 'Supplier Name'
, T2.OnOrder
, T2.IsCommited
, T2.OnHand
, T4.BINLABEL
, T4.QUANTITY
FROM RIN1 T0
INNER JOIN ORIN T1 ON T1.DocEntry = T0.DocEntry
INNER JOIN OITM T2 ON T2.ItemCode = T0.ItemCode
LEFT JOIN OCRD T3 ON T3.CardCode = T2.CardCode
LEFT JOIN A1Warehouse..BINLOCAT T4 ON T4.PRODUCT = T0.ItemCode collate SQL_Latin1_General_CP850_CI_AS
WHERE T1.DocDate >= @fromDate AND T1.DocDate <= @toDate
GROUP BY T0.ItemCode, T0.Dscription, T3.CardCode, T3.CardName, T2.OnOrder, T2.IsCommited, T2.OnHand, T4.BINLABEL, T4.QUANTITY
)Tx
GROUP BY Tx.[Item Code], Tx.Description, Tx.[Supplier Code], Tx.[Supplier Code], Tx.[Supplier Name], Tx.OnOrder, Tx.IsCommited, Tx.OnHand, Tx.BINLABEL, Tx.QUANTITY
)Ty
PIVOT
MAX(Ty.Quantity)
FOR Ty.Binlabel IN ([0], [1], [2])
)Tz
Here is a screen shot of the results that I see -
I understand why there are NULLs in my 0, 1, and 2 columns...there simply aren't Bin Labels called 0, 1 or 2!
My challenge is that I do not know how to proceed from here. Firstly how do I call each of the pivoted columns 'Bin 1', 'Bin 2', 'Bin...', 'Bin 26' when the actual Bin Labels are over 10 thousand different possible character sets, e.g.: #0005540, K1C0102, etc,
etc, etc...
I have considered the possibility that a WHILE loop may be able to serve in populating the column names...
DECLARE @maxBins int
DECLARE @loopCount int = 1
SET @maxBins = (SELECT MAX([# of Bins]) AS 'Max Bins'
FROM
SELECT
COUNT(BINLABEL) '# of Bins'
FROM A1Warehouse..BINLOCAT
GROUP BY PRODUCT
) AS T0)
PRINT @maxBins
WHILE @loopCount <= @maxBins
BEGIN
PRINT @loopCount
SET @loopCount = @loopCount +1
END
...of course the query above has no practical application at this stage, but I thought that it may be useful
from a 'logic' point of view.
I have tried to insert a WHILE clause into various locations within the Static Pivot query that I wrote, however in each instance there were errors produced by SSMS.
If anybody can suggest a way to solve my data pivoting challenge it will be much appreciated.
Kind Regards,
David

Answer 1

How you can 'assign' multiple values to the @SQL variable (if that is indeed what is happening)
What 'FOR XML PATH('') actually does
Dynamic SQL in general...
if you could share some insights into how I can go about removing the NULLs it will be greatly appreciated.
The FOR XML PATH('') method is one of several ways to concatenate the values from several rows into one column of one row.  There are other ways, but I believe the most commonly used one today (and certainly the one I always use) is the FOR XML method. 
A good link for understanding the FOR XML method is
http://bradsruminations.blogspot.com/2009/10/making-list-and-checking-it-twice.html.
If you are not used to dynamic SQL, there is an excellent discussion at http://www.sommarskog.se/dynamic_sql.html.  If you are not used to dynamic SQL, you definitely want to review the SQL Injection topic on that page before making extensive use of
dynamic SQL. 
You can get rid of the NULLs, but only by converting the NULLs into a value.  You can use the IsNull() function or as diadmin noted the Coalesce() function to do this.  There is, however, the question of what value do you want.  Of course
the obvious choice for converting varchar values (like BinLabel) is the empty string ('').  But for numeric values (like BinQty) you need to either output a number (like 0.000000) or you need to convert the numbers into a character type and then you could
use the empty string.  Of course doing this makes this already complex piece of SQL more complex, but it certainly can be done.  An example
Create Table Foo(ItemCode varchar(6), ItemDescription varchar(50), OrderQty decimal(12,6), BinLabel varchar(7), BinQty decimal(12,6));
Insert Foo(ItemCode, ItemDescription, OrderQty, BinLabel, BinQty) Values
('DR1124', 'D6 Series 24 OD 3/8 1 Neck', 50, 'B1A1904', 9),
('DR1124', 'D6 Series 24 OD 3/8 1 Neck', 50, 'M1D0703', 66),
('DR1124', 'D6 Series 24 OD 3/8 1 Neck', 50, 'S1K0603', 24),
('H21', 'Rubber Mallot', 75, 'X1X0712', 100),
('H21', 'Rubber Mallot', 75, 'T3B4567', 92);
Declare @SQL nvarchar(max);
;With cteRN As
(Select ItemCode, ItemDescription, BinLabel, BinQty,
Row_Number() Over(Partition By ItemCode Order By BinLabel) As rn
From Foo)
Select @SQL = (Select Cast(N'' As nvarchar(max)) + N', IsNull(Max(Case When rn = ' + Cast(rn As nvarchar(5)) + N' Then BinLabel End), '''') As BinLabel' + Cast(rn As nvarchar(5))
+ N', IsNull(Cast(Max(Case When rn = ' + Cast(rn As nvarchar(5)) + N' Then BinQty End) As varchar(19)), '''') As BinQty' + Cast(rn As nvarchar(5))
From (Select Distinct rn From cteRN) x
Order By rn
For XML Path(''))
Select @SQL = Stuff(@SQL, 1, 2, '');
--Select @SQL
Select @SQL = N'Select ItemCode, Max(ItemDescription) As ItemDescription, Max(OrderQty) As OrderQty,' + @SQL + N' From (Select ItemCode, ItemDescription, OrderQty, BinLabel, BinQty,
Row_Number() Over(Partition By ItemCode Order By BinLabel) As rn
From Foo) As x Group By ItemCode'
--select @SQL
Exec(@SQL);
-- Cleanup
go
Drop Table Foo;
Tom