title: ORACLE SQL: Reseting a counting sequence when ID ends for the next one
body: <p>I am currently trying to reset a sequence if an ID of a Customer ends
  right now, it is something like this:</p>
  <pre><code>CustomerID   Product PosNr
  1            Banana   1
  1            Papaya   2
  1            Apple    3
  2            Laptop   1
  2            Keyboard 2
  </code></pre>
  <p>I hope it is clear what I mean.
  The PosNr should reset for another Customer.</p>
  <p>Can I Set up something like this while inserting the values into the table, or in any other way?</p>