Question

Here are my tables:

-----------------------------------------
Hotels
-----------------------------------------
HotelID | HotelName
-----------------------------------------


-----------------------------------------
HotelImages
-----------------------------------------
HotelImageID | HotelID | Filename
-----------------------------------------

I’d like to create a SELECT statement that will return the data like so:

HotelID | HotelName | Images
-----------------------------------------
1 | Hotel1 | Image1,Image2,Image3
2 | Hotel2 | Image4,Image5,Image6

How can I modify my query to do this? I have:

SELECT H.HotelID, H.HotelName, '' AS Images
FROM Hotels H

I know I can use COALESCE to create a comma-delimited list:

DECLARE @Images varchar(500)
SELECT @Images = COALESCE(@Images + ',', '') + CAST(Filename AS varchar(100)) FROM HotelImages WHERE HotelID = 1
SELECT @Images

But I don’t know how to integrate that into my current query so that the list can be returned with the rest of the hotel data.

I should mention I’m using SQL Server 2000.

Answer 1

Since this is SQL 2000 you options are somewhat limited. You can’t use FOR XML PATH or recursive CTEs

Also the COALESCE trick only works for stuffing a comma delimited list for single hotel. Not all of them.

Honestly you’re better off doing this in the client. But if that can’t be done (certain Report Apps that-which-must-not-be-named come to mind) you can do the following.

Note the number of times the loop process is equal to maximum number of files associated with a hotel. This is much better than setting up a loop for each hotel (e.g. calling a UDF from the select clause).

DECLARE @foo table ( HotelID int , lastID int , FileNameList varchar(8000))

INSERT INTO @Foo 

SELECT
    start.HotelID,
    start.firstID ,
    id.FileName 

FROM
    (SELECT 
        HotelID,
        min(HotelImageID ) firstID
    from 
        HotelImages


    group by HotelID) start
    INNER JOIN HotelImages hi
    ON start.firstID = hi.HotelImageID 


WHILE @@RowCount <> 0 
BEGIN

    UPDATE @foo
    SET 
        FileNameList = FileNameList + ',' + FileName
        lastID  = Xnext.nextID
    FROM 
        @foo f
        INNER JOIN HotelImages hi
        ON f.HotelID = id.HotelID
        INNER JOIN 
        (SELECT 

            id.HotelID,
            min(HotelImageID ) nextID
        from HotelImages hi
              inner join @foo f
              on f.HotelID = id.HotelID
        where id.HotelImageID  > f.lastid


        group by id.HotelID) Xnext

        ON Xnext.nextID = id.HotelImageID 



END 

SELECT 
    h.HotelID 
    h.HotelName,
    f.FileNameList
FROM
    Hotels h
    INNER JOIN @foo f
    ON h.hotelId = f.HotelId