title: MySQL sub query with multiple columns
body: <p>After some research I now understand I cannot return multiple columns from a subquery. What can I do instead?</p>
  
  <pre><code> SELECT * FROM `users` WHERE `id` IN (SELECT `id1`, `id2` FROM `ids` WHERE `location` = 1)
  </code></pre>
  
  <p>The result is <code>#1241 - Operand should contain 1 column(s)</code></p>