trying to concatenate a column into a comma delimited list - sql

Question

i have 3 tables, 1 for products and one for categories the products are assigned to. what IM trying to do is concatenate the column called stCategoryName to a single column in a comma delimited list.
Basically I have the products table containing the primary key for each product and im trying to figure out how to concatenate all the stcategoryName column next to each product so i can have a simplified return
what im trying to get is the following.
stProductID stCategoryName
123 category1,category2,category3
SELECT
dbo.StoreItemTracking.StCategoryID,
dbo.StoreItemTracking.StProductID,
dbo.StoreItemTracking.viewOrder,
dbo.StoreCategories.StCategoryName,
dbo.Store_Products.PartNumber
FROM
dbo.StoreItemTracking
INNER JOIN dbo.StoreCategories
ON dbo.StoreItemTracking.StCategoryID = dbo.StoreCategories.StCategoryID
INNER JOIN dbo.Store_Products
ON dbo.StoreItemTracking.StProductID = dbo.Store_Products.ID
Im stuck as to how to concatenate a column where the query contains 3 tables to select from.
any help greatly appreciated

Answer 1

Look at using coalesce to turn category into a CSV:
See example:
DECLARE #EmployeeList varchar(100)
SELECT #EmployeeList = COALESCE(#EmployeeList + ', ', '')
+ CAST(Emp_UniqueID AS varchar(5))
FROM SalesCallsEmployees
WHERE SalCal_UniqueID = 1
SELECT #EmployeeList
You can also use CTE's or Subqueries. See:
http://archive.msdn.microsoft.com/SQLExamples/Wiki/View.aspx?title=createacommadelimitedlist
Another nice and easy example:
http://www.codeproject.com/Articles/21082/Concatenate-Field-Values-in-One-String-Using-CTE-i
This:
FId FName
--- ----
2 A
4 B
5 C
6 D
8 E
with:
;WITH ABC (FId, FName) AS
(
SELECT 1, CAST('' AS VARCHAR(8000))
UNION ALL
SELECT B.FId + 1, B.FName + A.FName + ', '
FROM (And the above query will return
SELECT Row_Number() OVER (ORDER BY FId) AS RN, FName FROM tblTest) A
INNER JOIN ABC B ON A.RN = B.FId
)
SELECT TOP 1 FName FROM ABC ORDER BY FId DESC
becomes:
FName
----------------------------
A, B, C, D, E,

Answer 2

Don't understand how your products and categories are connected but in general I do like this to create comma separated lists.
SELECT table1.Id
,Csv
FROM table1
CROSS APPLY (
-- Double select so we can have an alias for the csv column
SELECT (SELECT ',' + table2.Name
FROM table2
WHERE table2.Id = table1.Id
FOR XML PATH('')
) AS RawCsv
) AS CA1
CROSS APPLY (
-- Trim the first comma
SELECT RIGHT(RawCsv, LEN(RawCsv) - 1) AS Csv
) AS CA2