title: Bigquery multiple WITH clauses throwing error
body: <p>I am using BigQuery to run a query with multiple WITH clauses, as follows: </p>
  
  <pre><code>WITH subq_L1 AS (
      SELECT
          id,
          metric,
          COUNT(DISTINCT IF(DATEDIFF(TIMESTAMP('{execution_date:s}'), TIMESTAMP(ds)) &lt; 1, ds, NULL)) AS L1
      FROM
          [xxx:yyy.zzz]
      GROUP EACH BY
          id, metric
  ),
  subq_L7 AS (
      SELECT
          id,
          metric,
          COUNT(DISTINCT IF(DATEDIFF(TIMESTAMP('{execution_date:s}'), TIMESTAMP(ds)) &lt; 7, ds, NULL)) AS L7
      FROM
          [xxx:yyy.zzz]
      GROUP EACH BY
          id, metric
  ),
  subq_L14 AS (
      SELECT
          id,
          metric,
          COUNT(DISTINCT IF(DATEDIFF(TIMESTAMP('{execution_date:s}'), TIMESTAMP(ds)) &lt; 14, ds, NULL)) AS L14
      FROM
          [xxx:yyy.zzz]
      GROUP EACH BY
          id, metric
  )
  SELECT * FROM subq_L1
  UNION ALL
  SELECT * FROM subq_L7
  UNION ALL
  SELECT * FROM subq_L14
  </code></pre>
  
  <p>The '{execution_date:s}' gets formatted by python into a date-string.</p>
  
  <p>BigQuery keeps throwing this error:</p>
  
  <pre><code>Encountered " "WITH" "WITH "" at line 1, column 1. Was expecting: &lt;EOF&gt;.
  </code></pre>
  
  <p>All the queries run successfully if they stand alone; it is only putting them inside the WITH clause that makes it unsuccessful. </p>
  
  <p>Why are these not succeeding? </p>