title: SQL query with duplicate records
body: <p>I am trying to write a query in SQL server to find out if there are any multiple rows for each customer by customerID.
  Please let me know.</p>
  
  <p>Here is the table structure</p>
  
  <pre><code>Customer table
  -----------------------------------------
  orderID          CustName      CustomerID
  ---------------------------------------
  100               test           123456    
  101               test           123456
  
  Orders table
  ------------------------------------
  pID               OrderID
  -----------------------------------
  1                 100        
  2                 101
  </code></pre>