title: Change dataType from bigquery.Value to string
body: <p>I connect BigQuery with Go language as the following API documentation demonstrates,
  <a href="https://cloud.google.com/bigquery/docs/reference/libraries?hl=en_US" rel="nofollow noreferrer">https://cloud.google.com/bigquery/docs/reference/libraries?hl=en_US</a></p>
  <p>After that, I need to get sql results in specific row and column, and judge if it equals a specific string. Could I change bigquery.Value to string and how to do that?</p>