We need to get the sum of statistics data from the "beginning" which means from the moment we added site to the system (ts_created field in site table).
It can be very useful for example in video plugin when we can get the sum of all video events (i.e. video_play) from the first time video appeared online. It is quite important feature.
To do what you want to do, the best thing I can think of is to build a filter that would sum up the DataTable_Array of every year and output only the sum.this could look like:
?module=API&method=VisitFrequency.getVisitsReturning&idSite=1&period=year&date=last10&format=xml
&operation=sum
This filter could use the DataTable::addDataTable
The only thing to think of is that the DataTable_array could be simple:
date=A
data A
date=B
data B
looping over the set and sum the datatable should work.
For the version where the rows are themselves made of dataTable_Array
idsite=1
date=A
data A
date=B
data B
idsite=2
date=A
data C
date=B
data D
etc.
we want the output
idsite=1
data A+B
idsite=2
data B+D
