title: Oracle: normalized fields to CSV string
body: <p>I have some one-many normalized data that looks like this.</p>
  
  <pre><code>a | x
  a | y
  a | z
  b | i
  b | j
  b | k
  </code></pre>
  
  <p>What query will return the data such that the "many" side is represented as a CSV string?</p>
  
  <pre><code>a | x,y,z
  b | i,j,k
  </code></pre>