title: Mysql error: Subquery returns more than 1 row (but I want it to - I want to select a vector on each row)
body: <p>For the sake of simplicity, let's say I have tables <code>users</code> and <code>interests</code></p>
  
  <h2>users</h2>
  
  <pre><code>id | name
  ---------
  1  | amy
  2  | brian
  3  | carole
  </code></pre>
  
  <h2>interests</h2>
  
  <pre><code>uid | interest
  --------------
  1   | apples
  3   | catfish
  3   | cobwebs
  3   | cryogenics
  </code></pre>
  
  <p>What I want to get back is output that looks something like</p>
  
  <pre><code>name  | interests
  ----------------
  amy   | apples
  brian | 
  carole| catfish, cobwebs, cryogenics
  </code></pre>
  
  <p>Where interests could be a string consisting of the concatenation of all relevant values with some delimiter, or a vector of discrete values. I'm interested in dumping this to a file, rather than putting it in a table or doing any kind of further SQL stuff with it. Doing</p>
  
  <pre><code>SELECT name, (SELECT interest from interests where uid=id) as interests from users;
  </code></pre>
  
  <p>Is giving me the error I mentioned in the title. Is this just not possible in the SQL paradigm? I know I can dump a join of these tables to a file, and then aggregate the values I need using a python script or something, but this feels inelegant.</p>