title: How to get max of multiple columns in oracle
body: <p>Here is a sample table:</p>
  
  <pre><code>|           customer_token             |        created_date          | orders | views |
  +--------------------------------------+------------------------------+--------+-------+
  | 93a03e36-83a0-494b-bd68-495f54f406ca | 10-NOV-14 14.41.09.000000000 |    1   |   0   |
  | 93a03e36-83a0-494b-bd68-495f54f406ca | 20-NOV-14 14.41.47.000000000 |    0   |   1   |
  | 93a03e36-83a0-494b-bd68-495f54f406ca | 26-OCT-14 16.14.30.000000000 |    2   |   0   |
  | 93a03e36-83a0-494b-bd68-495f54f406ca | 11-OCT-14 16.31.11.000000000 |    0   |   2   |
  </code></pre>
  
  <p>In this customer data table I store all of the dates when a given customer has placed an order, or viewed a product. Now, for a report, I want to write a query where for each customer (auth_token), I want to generate the last_order_date (row where orders > 0) and last_view_date (row where product_views > 0).</p>
  
  <p>I am looking for an efficient query as I have millions of records.</p>