title: Presto check if NULL and return default (NVL analog)
body: <p>Is there any analog of NVL in Presto DB?</p>
  
  <p>I need to check if a field is NULL and return a default value.</p>
  
  <p>I solve this somehow like this:</p>
  
  <pre><code>SELECT
    CASE 
      WHEN my_field is null THEN 0 
      ELSE my_field 
    END
  FROM my_table
  </code></pre>
  
  <p>But I'm curious if there is something that could simplify this code.</p>