I have used the dual() function in chart's expression, however, the chart show all the original value in data point not what I want by using dual. Could any one please help to tell why the dual function could not work?
A dual is actually a number with a custom text representation. The option is show the value on the data points, so it is displaying the numeric value, not your text representation. I am not sure what output you are trying to get, but I am not sure if its possible with an area chart.
Logic will get you from a to b. Imagination will take you everywhere. - A Einstein