Apache NiFi RecordPath Guide
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Normally, when a path is given to a particular field in a Record, what is returned is the value of that field. It can sometimes be useful, however, to obtain the name of the field instead of the value. To do this, we can use the fieldName function.


Return value


workAddress and homeAddress

//city[not(startsWith(fieldName(..), 'work'))]

Jersey City

In the above example, the first RecordPath returns two separate field names: "workAddress" and "homeAddress". The second RecordPath, in contrast, returns the value of a "city" field and uses the fieldName function as a predicate. The second RecordPath finds a "city" field whose parent does not have a name that begins with "work". This means that it will return the value of the "city" field whose parent is "homeAddress" but not the value of the "city" field whose parent is "workAddress".