Ability to show year over year data on a graph

1

I would like the ability to show year over year data on a graph where the series is the year for the data being graphed. This way its easy to see improvement over last year.

2

Grant,

To this old question you posted, did you ever figure out how to impliment it? I have tried Left JOIN, nested SQL and UNION. Nothing is giving me what I want.

I have sales against a timestamp, want to sum weekly sales this year, and last, in a 2-series chart.

you input appreiciated.
Chuck