Ask attributs between two inputs

CélineLE_HIR

Hello everyone! 

I have a question, I work on a project with two features. First feature, call "FL" have an attribut named "PK", it's a double attribut. And the second feature, named "NAV" have an other PK attribut. This two PK attribut have differents values.   

We need to ask NAV, if it's close to the first, FL. (We have work with field calculator to have a notion about "near"). But we can't ask if NAV's PK is close to PK's FL. Have you a solution about this problem ?

The final aim is to obtain an alert when NAV is at a PK close to FL.

Have a good day.
Lucille