Re: How to search missing value on the app Qilksense?
Using what I suggested would give you an additional field value Missing_Amount that you can use in the search box.
Also please consider the data you have and make difference between NULLs and zero-length strings. A zero-length string would appear as an empty selectable field in you filter pane. NULL would not and you cannot search or select NULLs unless you do something on the back end.