Simon,

you should allow multiple string concatenation using ',' in all your datasets.

for instance if you are using

select item_id, item_desc from Items

instead of that

USE ---

-----------------------

Declare @ParamItem varchar(1000),

@StringVARCHAR(500)

set @Paramitem = @item

Declare @temp table (item_id int, item_desc varchar(100))

Begin

WHILE LEN(@Paramitem) > 0

BEGIN

SET @String= LEFT(@Paramitem, ISNULL(NULLIF(CHARINDEX(',', @Paramitem) - 1, -1), LEN(@Paramitem)))

SET @Paramitem = SUBSTRING(@Paramitem, ISNULL(NULLIF(CHARINDEX(',', @Paramitem), 0), LEN(@Paramitem)) + 1, LEN(@Paramitem))

insert into @temp (item_id , item_desc )

select distinct item_id , item_desc from ITEM

END END

select distinct item_id , item_desc from @temp

-----------------------

do remember that ssrs is case sensitive. HTH