11-17-2016 11:03 AM
Generally speaking, I wouldn't imagine it being a good idea. However without any refrence to how you want it to look its hard to say. You could just overlay a line plot going up the Y axis with datalabels showing the additional data you want, i.e if your x goes 0-10, and y 1-5, then do x values 0.5, 1, 2, 3..., and overlay a line plot with values 1-5 and datalables on., would look like an axis then.
Here is a good site for graphs, and examples.
11-17-2016 11:07 AM
No, not automatically.
If you want to go "old school," you can use an affine transformation to transform the Y3 values to one of the other scales, then use annotation to put your own Y3 axis inside the plot area.
Another option is to show the data by using a paneled display instead of an overlay. You can use the SGPANEL procedure to create multiple plots that each have their own scale. You would use the UNISCALE= option in teh PANELBY statement to allow scales to float between panels.
11-17-2016 01:46 PM
Although you can, should you? Generally not - it leads to reader confusion. If the idea is to maximize the use of "real estate" (fewer pages), there's usually no reason why 2 or three smaller charts on a single page can't be used.