Question

I’ve seen many rows-to-columns threads here but can’t find exactly what I’m looking for.

How do you convert the following table:

ID    Foo    Bar
1     A      F
2     B      G
3     C      H
4     D      I
5     E      J

Into this:

ID    1    2    3    4    5
Foo   A    B    C    D    E
Bar   F    G    H    I    J

Thanks! I am using SQL Server 2005 by the way.

Answer 1

Here is an answer. As I alluded to in my comment, this only works in the dimensions that you’re working with are known/fixed. First, the sample data:

declare @Table table (ID int not null,Foo char(1) not null,Bar char(1) not null)
insert into @Table (ID,Foo,Bar)
select 1,'A','F' union all
select 2,'B','G' union all
select 3,'C','H' union all
select 4,'D','I' union all
select 5,'E','J'

select * from @Table --As per your original data table

;with Rot1 as (
    select
        *
    from
        @Table unpivot (Value for Col in (Foo,Bar)) t
)
select * from Rot1 -- See below

;with Rot1 as (
    select
        *
    from
        @Table unpivot (Value for Col in (Foo,Bar)) t
), Rot2 as (
    select
        *
    from Rot1 pivot (MAX(Value) for ID in ([1],[2],[3],[4],[5])) t
)
select * from Rot2 -- As per your required result

The output when merely selecting from Rot1 is:

ID  Value   Col
1   A   Foo
1   F   Bar
2   B   Foo
2   G   Bar
3   C   Foo
3   H   Bar
4   D   Foo
4   I   Bar
5   E   Foo
5   J   Bar

So, we can construct this query, so long as we know all of the cross-referencing identifiers, e.g. Foo, Bar, 1, 2, 3, 4, and 5. In most cases of wanting to do this kind of transform, you don’t know all of these values, and so SQL isn’t the way to achieve the transform – use whatever tool is consuming the original results to achieve this kind of reformatting.