title: How to show postgresql expression type?
body: <p>I would like to show any expression type name.
  Something like 'type' function in python.</p>
  
  <p>To work somewhat like these:</p>
  
  <pre><code>select type(1);
  'int'
  
  select type(ROW(1, 'abc'));
  'row(int, text)'
  
  select type(select * from t1);
  'setof t1'
  </code></pre>
  
  <p>Is there anything like this in postgresql?</p>