All (or None) filter values in a Expression filter using a parameter

Question

What is the syntax to default to All or None values within an expression filter for a Viz?

For example, lets say I have a filter prompt bound to pv_customername, defaulting to 'All'

I want to filter a viz by this filter only when the user selects a value otherwise it should bring back all results or not filter on this column at all.

Customer_Name IN (@parameter(pv_customername)('%')

What is the correct syntax for % to do this?

Jayko Paten · Accepted Answer

Answering my own Q here:

The syntax I found is

Customer_Name IN (@parameter(pv_customername)(Customer_Name)

Rajakumar Burra · Accepted Answer

Customer_Name IN (@parameter(pv_customername)('') - Will provide parameter values as a default value.

Customer_Name IN (@parameter(pv_customername)(Customer_Name) - Will provide the value you mentioned irrespective of parameter value.