title: SQLite3 Select Statement Query
body: <p>I have the following sqlite3 table, BookAuthor:</p>
  
  <pre><code>BookID    AuthorID
  B13       A02
  B13       A67
  B13       A13
  B02       A02
  B02       A67
  B45       A02
  B45       A13
  B33       A02
  </code></pre>
  
  <p>And want to produce this one:</p>
  
  <pre><code>Author1  Author2 NumCoAuthored
  A02      A67     2
  A02      A13     2
  A67      A13     1
  </code></pre>
  
  <p>I need help writing the sql select statement. I don't even know where to start or if it's possible.</p>
  
  <p>Kindly note that the data set is really large (more than 10 GB) and I'm guessing i might have to do it in chunk sizes. </p>
  
  <p>So maybe I should order by AuthorID and do it each author at a time with every other Author? </p>