title: Does Presto have the equivalent of Hive's SET command
body: <p>It's very convenient to be able to set script variables.  For example,</p>
  
  <p>SET start_date = 20151201;</p>
  
  <p>SELECT * FROM some_table where date = {$hiveconf:start_date};</p>
  
  <p>Does Presto have this capability?</p>