title: RedShift: How to cast integer with year into a date?
body: <p>Assume a user tries to cast a number (year of birth) into a date.</p>
  
  <pre><code>select year_of_birth, cast(year_of_birth as date) from visit_occurrence 
  </code></pre>
  
  <p>And gets this error :</p>
  
  <pre><code>cannot cast type smallint to date
  </code></pre>
  
  <p>What is the proper way?
  e.g., cast(cast(YOB as string)+'-01-01' as date) does not work either.</p>