Extreme of Selection, Disregard Dimension?

[#1]

hi, there. In the chart below, with legend 'interval' I'd like to show, by the last date selected, how long hasn't a type of weather occurred.

For instance, I selected date ranges from 2011-01-01 to 2011-01-21, while total dates in the chart expanding from 2011-01-01 to 2011-02-05. So for 'sun', the 'interval' bar should display, by the end of 2011-01-21, there has been 7 days without a sunny day.

Who knows such expressions?

In the demo chart (results are wrong), I use max({1}Date)-max(Date).

Rgds

ALKshthsk

[#2]

That's indeed what I need. lol