SQL Select Distinct -

I think it is very easy, I was expecting verification.

I have 2 columns: ID & amp; Document number This is one-to-many relationships, an ID can have several document numbers.

I need to get the ID, where all the document numbers related to it are unique.

What is this group, for what is in combination with? Is it simple (as you suspect) using it as idle by ID

A simple group BY / hovering and DISTINCT ;

  Selection ID from the ID of the data ID from ID (DocumentNumber) = COUNT (inherent DocumentNumber)   
.