#Multivalue error solutions

Hi All,

I need help to understand #Multivalue error solutions. There are 2 ways to resolve this issue.

1. Set automatically aggregated at universe level

2. Check the box "Avoid duplicate rows aggregation"

I am unable to understand these solutions. e.g. suppose in a report I have Input control that contains a list of cities, selecting a city will update a chart to display the data for city. The name of the city is displayed as the Title label for chart. But if user select "All Values" option in the input control, I get #Multivalue error.

Then in this case how can we solve this issue using above 2 solutions or is there any other way?

Thanks in advance.

Shweta