title: Sql distinct selective row after a join question
body: <p>Let's say i have 2 tables Customer and Books.</p>
  
  <p>Table Books can have multiple rows that pertain to a row in Customer.</p>
  
  <p>Ex:
  customer John Doe has an id of 1000.
  Table Books has 2 rows with a member_id column with 1000 (John Doe).</p>
  
  <p>These 2 rows are identical EXCEPT one of the fields (book title) is empty. The other row has a value for a title.</p>
  
  <p>Question:
  How can i query this so that I retrieve the row with the valid title value, BUT, if both title values are empty, then it just returns a single row?</p>
  
  <p>I certainly hope that made sense.</p>