SharePoint 2010, filtered view

The aspect of the view is easy, there are a lot of options to enable the visualization in the right way.

The only problem I have faced is within the filtering. I have tried to use brackets to point to other fields (for instance: [field_A] ) with the purpose of showing just the documents where the approver is equal to the responsible.

Reading on the internet I have found that the right way to do it is not with the filter option of the view. The proposed solution I found is creating a calculated column on the view.

I have added this formula: =IF([Field_A]=[Field_B],”Is Equal”,”Is Different”)

but this error is always shown:

Let’s continue working on this funny activity,