Right now, the 'calculate' function only counts circulation from the old_issues table, and not issues.
If you generate a report of Most Circulated Items, you get a list of titles and their respective number of checkouts.
When you click on one of the titles you see all the details about that record,
from that screen you can view the checkout history of that record.
The figures of Number of checkouts from the generated report(Most Circulated Items) and the checkout history for that record are different.
Created attachment 29959 [details] [review]
This patch depends on my patch http://bugs.koha-community.org/bugzilla3/attachment.cgi?id=29958 for bug http://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=12628
This adds a union for `old_issues` and `issues`. Filtering that applied to `old_issues` before joins has been applied prior to the union on both `issues` and `old_issues`. Two new variables have been added to accomplish this $strsth2_filter and $strcalc_filter. The union is named as `circulated`. Where appropriate `old_issues` has been replaced with `circulated`.