I tried to make a web-based report in a graph. In which I need to calculate the amount of used space on all volumes on a server for a certain time interval.
I chose the volumes in the source and noted the checkbox "Show the sum of all data series. The graph shows all volumes, not just the sum of the volumes. I need to on the chart was only the sum, without chart for each volume.
I think this can be done using SQL query in the source.
But I don't know how to build difficult queries.
Can anyone help?