The check-ins statistical report shows wrong data (at least) if you choose itemtype -> column and grouping by month. Steps to reproduce: - Go to Reports > Circulation statistics - Choose a period (row) when there is circulation - Choose to group 'Checkout' by month - Run report => SUCCESS: you see checkouts numbers by month and by item type - Go back and choose to group 'Checkin' by month - Run report => FAILURE: you see all cells contain zeros (and they shouldn't) and there is a weird NULL column, with the sum of the checkins (same value as 'Total' column).
I tested this and it goes back (at least) up to 3.12.x
Created attachment 40991 [details] Correct (checkouts)
Created attachment 40992 [details] Wrong (checkins)
I forgot to add a step: choose to group by itemtypes in columns.
*** This bug has been marked as a duplicate of bug 14598 ***