title: How to keep a rolling counter on unique dates in SQL? (ORACLE)
body: <p>I have a Customer field and a Date field, and I want my data to look like this:</p>
  
  <pre><code>Customer | Date  | Count 
  =========================
   Frank   | 02/01 |  1 
   Frank   | 03/22 |  2
   Frank   | 12/20 |  3
   Mary    | 01/14 |  1
   Mary    | 05/15 |  2
   Mary    | 11/28 |  3
   Mary    | 12/01 |  4 
   Vince   | 06/09 |  1
   Vince   | 09/09 |  2
  </code></pre>
  
  <p>Basically a consecutive counter per Customer and per Date.   </p>
  
  <p>Thank you. </p>