> Oh, I just noticed the subselect clause, where each subselect is applying
> the SAME alias to the subselected column. This led me to rethink your
> query. Of course, what you are looking to do here needs to be done with a
> UNION query because all of the columns in your dataset have 3-way
> ambiguity. This, after all, would be the main reason for your problem.
>
> As the statement stands, the query logically should return one column for
> each one selected, i.e. a total of 18 columns. I suspect this isn't what
> you are after, anyway. If it *is* what you want, then apply an alias to
> each column in 'B' and 'C' to remove the ambiguities.
>

Sorry, but my english is not so good, therefore I haven't understood, what you
mean. Can you explain it to me a little bit more easier :-)