CAML Query for item where one value is the maximum and another is not null

Question

What I am trying to do is fetch a single list item that has the highest ID, but also has a value in the Shelf field. Below is my query, which I am pretty sure I formatted correctly.

<View>
  <Query>
    <Where>
      <IsNotNull>
        <Field RefName='Shelf'/>
      </IsNotNull>
    </Where>
    <OrderBy>
      <FieldRef Name='ID' Ascending='False' />
    </OrderBy>
  </Query>
  <RowLimit>1</RowLimit>
</View>

However, when I test the code I get the error

Request failed. One or more field types are not installed properly. Go to the list settings page to delete these fields.

undefined

I am not sure what it is that is going wrong, since I checked that I am using the actual column name, not the display name (which are the same in this case anyway).

Answer 1

Use <FieldRef Name='Shelf'/> instead of <Field RefName='Shelf'/>