HowTo Convert Table Values to Comma-Delimited String

We have 2 tables related as one-to-many. How can we fetch parent table field, and child table values comma-delimited ? The function below demonstrates a technique how to convert table values into comma-delimited string with one query.

 

ALTER FUNCTION F_GET_STR

(@p_order_id int)

RETURNS varchar(1000)

AS

    BEGIN

 

    DECLARE @p_str VARCHAR(1000)

    SET @p_str = ''



    SELECT @p_str = @p_str + ',' + CAST(productid AS VARCHAR(6))

      FROM [order details]

     WHERE orderid = @p_order_id



    RETURN @p_str



END

　　

Use this way:

 

SELECT orderid

          ,dbo.F_GET_STR(orderid)

      FROM orders