How to use PIVOT in SQL Server 2005 Stored Procedure Joining Two Views

Question

Good Morning,

I have 2 views: ICCUDays which contains one record per account with fields ACCOUNT and ICCUDays, ICCUEnctrSelectedRevCatsDirCost which contains multiple records per account with fields ACCOUNT, UBCATEGORY, and DirectCost.

My Goal: To create a stored procedure that outputs one record per ACCOUNT with ICCUDays and DirectCost by UBCATEGORY. This will be a crosstab or pivot and has to allow for the possibility of nulls in one or more direct cost ubcategory bucket. Finally, this crosstab or pivot needs to be sent to a new table EnctrUBCatPivot.

Questions: What is the correct PIVOT syntax for the above scenario? Given that I want to ouptut direct cost for however many UBCATEGORY entries, how do I write the TSQL to iterate over these and pivot by account and UBCATEGORY? Is all this accomplished in one sproc, or does it have to be separated into multiple sprocs to write the results out to a table?

Here's the code I've written so far:

ALTER PROCEDURE [dbo].[spICCUMain]
-- Add the parameters for the stored procedure here

AS
declare @columns varchar(8000)

BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.
SET NOCOUNT ON;

-- Insert statements for procedure here
SELECT @columns = COALESCE(@columns + ',[' + cast(UBCATEGORYmid as varchar) + ']','[' + cast(UBCATEGORYmid as varchar)+ ']')
FROM vwICCUEnctrSelectedRevCatsDirCost
GROUP BY UBCATEGORYmid


DECLARE @query VARCHAR(8000)

SET @query = '
SELECT *
FROM vwICCUEnctrSelectedRevCatsDirCost
PIVOT
(
MAX(DirectCost)
FOR [UBCATEGORYmid]
IN (' + @columns + ')
)
AS p'

EXECUTE(@query)

END

This works fine in that it outputs Account and all the Direct Costs for each UBCATEGORY. However, I need to inner join to vwICCUDAYS on ACCOUNT to add a column to the pivot for ICCUDays. Final pivot columns should be Account, ICCUDays, Direct Cost for each UBCATEGORYmid.

I'm not very familiar with the coalesce syntax and thus cannot discern how to modify it to add further columns, nor am I sure how/where to add the inner join syntax to add ICCUDays.

Can someone point me in the proper direction? Thanks, Sid

Answer 1

You need to know all of the possible values to PIVOT by. So it is difficult to do this with T-SQL directly unless you use dynamic SQL and this can get hairy pretty quickly. Probably better to pass all of the rows back to the presentation tier or report writer and let it turn them sideways.

Here is a quick PIVOT example if you know all of the UBCategory values in advance. I left out ICCUDays since it seems rather irrelevant unless there are columns that come from that view as part of the result.

USE tempdb;
GO
SET NOCOUNT ON;
GO

-- who on earth is responsible for your naming scheme?
CREATE TABLE dbo.ICCUEnctrSelectedRevCatsDirCost
(
    Account INT,
    UBCategory VARCHAR(10),
    DirectCost DECIMAL(9,2)
);

INSERT dbo.ICCUEnctrSelectedRevCatsDirCost
    SELECT 1, 'foo', 5.25
    UNION SELECT 1, 'bar', 6.25
    UNION SELECT 1, 'smudge', 8.50
    UNION SELECT 2, 'foo', 9.25
    UNION SELECT 2, 'brap', 2.75;

SELECT Account,[foo],[bar],[smudge],[brap] FROM 
    dbo.ICCUEnctrSelectedRevCatsDirCost
    -- WHERE <something>, I assume ???
PIVOT
(
    MAX(DirectCost)
    FOR UBCategory IN ([foo],[bar],[smudge],[brap])
) AS p;

GO
DROP TABLE dbo.ICCUEnctrSelectedRevCatsDirCost;

To make this more dynamic, you'd have to get the comma separated list of DISTINCT UBCategory values, and build the pivot on the fly. So it might look like this:

USE tempdb;
GO
SET NOCOUNT ON;
GO

-- who on earth is responsible for your naming scheme?
CREATE TABLE dbo.ICCUEnctrSelectedRevCatsDirCost
(
    Account INT,
    UBCategory VARCHAR(10),
    DirectCost DECIMAL(9,2)
);

INSERT dbo.ICCUEnctrSelectedRevCatsDirCost
    SELECT 1, 'foo', 5.25
    UNION SELECT 1, 'bar', 6.25
    UNION SELECT 1, 'smudge', 8.50
    UNION SELECT 2, 'foo', 9.25
    UNION SELECT 2, 'brap', 2.75
    UNION SELECT 3, 'bingo', 4.00;

DECLARE @sql NVARCHAR(MAX),
    @col NVARCHAR(MAX);

SELECT @col = COALESCE(@col, '') + QUOTENAME(UBCategory) + ','
    FROM 
    (
        SELECT DISTINCT UBCategory
        FROM dbo.ICCUEnctrSelectedRevCatsDirCost
    ) AS x;

SET @col = LEFT(@col, LEN(@col)-1);

SET @sql = N'SELECT Account, $col$ FROM 
    dbo.ICCUEnctrSelectedRevCatsDirCost
    -- WHERE <something>, I assume ???
PIVOT
(
    MAX(DirectCost)
    FOR UBCategory IN ($col$)
) AS p;';

SET @sql = REPLACE(@sql, '$col$', @col);

--EXEC sp_executeSQL @sql;
PRINT @sql;

GO
DROP TABLE dbo.ICCUEnctrSelectedRevCatsDirCost;

Then to "send the data to a new table" you can just make the query an INSERT INTO ... SELECT instead of a straight SELECT. Of course, this seems kind of useless, because in order to write that insert statement, you need to know the order of the columns (which isn't guaranteed with this approach) and you need to have already put in columns for each potential UBCategory value anyway, so this seems very chicken and egg.