title: Multiple text fields in a single query using group_concat
body: <p>I'm new to MySQL, and am using it to manage a database of books. Each book has, in addition to its standard data and description, some miscellaneous text fields, which may depend on the book. For example a book might have a few reviews, links, etc.</p>
  
  <p>I thought I'd store these in a table with the book_id, the field type (for example review), and the field contents.</p>
  
  <p>Now, my problem is that when I obtain all the data for a single book, I'd like to optimize the query. It'd be simple enough to get all the additional text field data with a second query. However, would there be a significant performance gain if I were to use group_concat to give me all the book information, including these additional text fields, in a single query?</p>
  
  <p>This means I'd also have to make sure my separator character is escaped, and I'd have to unescape it after obtaining the data. Which approach would work better for me?</p>
  
  <p>Thanks!</p>