Question

I’ve searched high and low for the answer to this, but I can’t figure it out. I’m relatively new to SQL Server and don’t quite have the syntax down yet. I have this datastructure (simplified):

Table "Users"         | Table "Tags":
UserID    UserName    | TagID    UserID    PhotoID
1         Bob         | 1        1         1
2         Bill        | 2        2         1
3         Jane        | 3        3         1
4         Sam         | 4        2         2
-----------------------------------------------------
Table "Photos":              | Table "Albums":
PhotoID   UserID    AlbumID  | AlbumID     UserID
1         1         1        | 1           1
2         1         1        | 2           3
3         1         1        | 3           2
4         3         2        |
5         3         2        |

I’m looking for a way to get the all the photo info (easy) plus all the tags for that photo concatenated like CONCAT(username, ', ') AS Tags of course with the last comma removed. I’m having a bear of a time trying to do this. I’ve tried the method in this article but I get an error when I try to run the query saying that I can’t use DECLARE statements… do you guys have any idea how this can be done? I’m using VS08 and whatever DB is installed in it (I normally use MySQL so I don’t know what flavor of DB this really is… it’s an .mdf file?)

Answer 1

I’d create a UDF:

create function GetTags(PhotoID int) returns @tags varchar(max)
as
begin
    declare @mytags varchar(max)
    set @mytags = ''

    select @mytags = @mytags + ', ' + tag from tags where photoid = @photoid

    return substring(@mytags, 3, 8000)
end

Then, all you have to do is:

select GetTags(photoID) as tagList from photos