title: Finding First Occurrence Based on Multiple Criteria
body: <p>I have a database where every customer have single cust_date, multiple sale date and sale count.  I need pull out data based on the first time that the customer has sale count greater than 0.  Here is a sample data:</p>
  
  <pre><code>ID      CUST_DATE      SALE_DATE      SALE_CNT
  7      4/20/2009      4/21/2009      0
  7      4/20/2009      4/22/2009      0
  7      4/20/2009      4/23/2009      5
  7      4/20/2009      4/24/2009      3
  27      4/21/2009      4/21/2009      4
  27      4/21/2009      4/22/2009      0
  27      4/21/2009      4/23/2009      2
  27      4/21/2009      4/24/2009      0
  28      4/20/2009      4/21/2009      1
  28      4/20/2009      4/22/2009      0
  28      4/20/2009      4/23/2009      0
  28      4/20/2009      4/24/2009      0
  32      4/21/2009      4/21/2009      0
  32      4/21/2009      4/22/2009      0
  32      4/21/2009      4/23/2009      0
  32      4/21/2009      4/24/2009      0
  34      4/21/2009      4/21/2009      0
  34      4/21/2009      4/22/2009      0
  34      4/21/2009      4/23/2009      0
  34      4/21/2009      4/24/2009      0
  44      4/20/2009      4/21/2009      0
  44      4/20/2009      4/22/2009      3
  44      4/20/2009      4/23/2009      0
  44      4/20/2009      4/24/2009      0
  </code></pre>
  
  <p>I need my final data to look like the below:</p>
  
  <pre><code>ID      CUST_DATE      SALE_DATE      SALE_CNT
  7      4/20/2009      4/23/2009      5
  27      4/21/2009      4/21/2009      4
  28      4/20/2009      4/21/2009      1
  44      4/20/2009      4/22/2009      3
  </code></pre>
  
  <p>Your assistance will be greatly appreciated.</p>
  
  <p>Thanks</p>