Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
> All you need to do is decide where you are going to store the level
> number and add it as a system attribute (negative attribute number).
This could only work if LEVEL is guaranteed to have one and only one
value per tuple. I'm not too sure about the spec but it seems like
that'd probably fall down in join situations.
regards, tom lane