title: DATEDIFF in SPARK SQl
body: <p>I am new to Spark SQL. We are migrating data from SQL server to Databricks.
  I am using SPARK SQL . Can you please suggest how to achieve below functionality in SPARK sql for the below datefunctions. I can see datediff gives only days in spark sql.</p>
  <pre class="lang-sql prettyprint-override"><code>DATEDIFF(YEAR,StartDate,EndDate)
  DATEDIFF(Month,StartDate,EndDate) 
  DATEDIFF(Quarter,StartDate,EndDate)
  </code></pre>