sql server - Dynamic SQL to generate column names?

Question

I have a query where I'm trying pivot row values into column names and currently I'm using SUM(Case...) As 'ColumnName' statements, like so:

SELECT
SKU1,
SUM(Case When Sku2=157 Then Quantity Else 0 End) As '157',
SUM(Case When Sku2=158 Then Quantity Else 0 End) As '158',
SUM(Case When Sku2=167 Then Quantity Else 0 End) As '167'
FROM
OrderDetailDeliveryReview
Group By
OrderShipToID,
DeliveryDate,
SKU1 

The above query works great and gives me exactly what I need. However, I'm writing out the SUM(Case... statements by hand based on the results of the following query:

Select Distinct Sku2 From OrderDetailDeliveryReview 

Is there a way, using T-SQL inside a stored procedure, that I can dynamically generate the SUM(Case... statements from the Select Distinct Sku2 From OrderDetailDeliveryReview query and then execute the resulting SQL code?

Answer 1

Having answered a lot of these over the years by generating dynamic pivot SQL from the metadata, have a look at these examples:

SQL Dynamic Pivot - how to order columns

SQL Server 2005 Pivot on Unknown Number of Columns

What SQL query or view will show "dynamic columns"

How do I Pivot on an XML column's attributes in T-SQL

How to apply the DRY principle to SQL Statements that Pivot Months

In your particular case (using the ANSI pivot instead of SQL Server 2005's PIVOT feature):

DECLARE @template AS varchar(max)
SET @template = 'SELECT 
SKU1
{COLUMN_LIST}
FROM
OrderDetailDeliveryReview
Group By
OrderShipToID,
DeliveryDate,
SKU1
'

DECLARE @column_list AS varchar(max)
SELECT @column_list = COALESCE(@column_list, ',') + 'SUM(Case When Sku2=' + CONVERT(varchar, Sku2) + ' Then Quantity Else 0 End) As [' + CONVERT(varchar, Sku2) + '],' 
FROM OrderDetailDeliveryReview
GROUP BY Sku2
ORDER BY Sku2

Set @column_list = Left(@column_list,Len(@column_list)-1)

SET @template = REPLACE(@template, '{COLUMN_LIST}', @column_list)

EXEC (@template)