OK, unfortunately groups aren’t going to work for you because the query builder is going to try to strip the column names out and it’s not possible if one of the things you’re selecting is CAST(column /10 as INTEGER) but I’ve found a workaround.
open CPA and execute the following query using the query builder tool under the advanced menu (make sure you change the columns and tables to match your own):
SELECT ImageNumber, obcount as count, CAST(obcount/10 as INTEGER) as count_tenth, CAST(obcount/20 as INTEGER) as count_twentieth FROM per_image
save this table to the database File>save table to database …name it “object_counts”
then close CPA, and open your props file and add the following groups:
group_SQL_count_tenth = SELECT per_image.ImageNumber, object_counts.count_tenth FROM per_image, object_counts WHERE per_image.ImageNumber=object_counts.ImageNumber
group_SQL_count_twentieth = SELECT per_image.ImageNumber, object_counts.count_twentieth FROM per_image, object_counts WHERE per_image.ImageNumber=object_counts.ImageNumber
re-run CPA, and open box plot.
Choose OTHER TABLE from the table drop down
Choose object_counts, per_image, NO, OK
Now you can pick whatever measurement from any of your tables and select count_tenth or count_twentieth from the group-by dropdown. The values on the x axis will be 1/10th or 1/20th of the original value.