title: How to SHOW COLUMNS from a SELECT query (rather than a table)?
body: <p>I get a syntax error when I run the following:</p>
  
  <pre><code>show columns from (select * from (select * from my_table) as T)
  </code></pre>
  
  <p>How can I show the columns from a query that I wrote, rather than from a table?</p>