title: Update with join with BigQuery
body: <p>Is it possible to do an UPDATE on a table based on a JOIN with an existing table in BigQuery?</p>
  
  <p>When I try this statement on the following database (<a href="https://bigquery.cloud.google.com/dataset/pfamdb:pfam31" rel="noreferrer">https://bigquery.cloud.google.com/dataset/pfamdb:pfam31</a>),</p>
  
  <pre><code>  UPDATE pfam31.uniprot
    SET uniprot.auto_architecture = uniprot_architecture.auto_architecture
    INNER JOIN
        pfam31.uniprot_architecture using(uniprot_acc)
  </code></pre>
  
  <p>I get errors relating to the <code>INNER JOIN</code>, with <code>WHERE</code> being expected instead. How should I be doing this (if it's possible)?</p>