Am I correct in believing that you can't merge from a view, or vice versa? My use case is this:
I have a table of entries which can be active or inactive. I want to show the active ones on the map with icons depending on a column value. So my plan was to do a view of only the active entries, and then merge with a lookup table from column value to label code. Conceptually, the reverse order would work just as well. But neither one of these actually works. I can't create a view from a merge at all, and when I try to merge from a view, the view tabled merge-column selector is greyed out, so I can't select its merge column.
Does this just plain not work? Or am I missing the right approach?
Unfortunately you aren't missing anything -- you can't merge with a view or create a view of a merge. The closest you can get is to do your merge, add the appropriate filter, download the filtered results to CSV, and reimport to a new table.
Alternatively you can do the merge and add a map tab with a filter for the active values. Depending on how you want to use the data, that might be enough; for instance, you can embed the filtered map or use the query in a FusionTableLayer call.