title: BigQuery - SQL convert string in Month DD, YYYY format to DATE
body: <p>I'd like to input a string in long month format (&quot;December 31, 2020&quot;) and get out a DATE value.</p>
  <p>I've tried <code>CAST(input_str as DATE)</code> and <code>CONVERT(DATE, input_str)</code> but neither do the trick. For CONVERT third argument, I see 107 as the shortened month style but can't find one for the lengthened month string.</p>
  <p>Thanks in advance.</p>
  <p>EDIT: underlying database is MYSQL, querying via Google Cloud Platform</p>