SELECT
  IF(a.URL IS NOT NULL,a.URL,b.URL) BaseURL,
  IF(a.PreviousURL IS NOT NULL,a.PreviousURL,b.NextURL) URL,
  a.NUMBER PreviousPageQuantity,
  b.NUMBER NextPageQuantity
FROM (
  SELECT
    URL,
    PreviousURL,
    COUNT(PreviousURL) NUMBER
  FROM (
    SELECT
      sessionId,
      TIME,
      URL,
      NUMBER,
      LAG(URL) OVER (PARTITION BY sessionId ORDER BY TIME) PreviousURL
    FROM (
      SELECT
        sessionId,
        hits.TIME TIME,
        hits.pagePath URL,
        RANK() OVER (PARTITION BY sessionId ORDER BY hits.TIME ASC) NUMBER
      FROM
        [owox-demo:OWOXBI_Streaming.session_streaming_20160711]
      WHERE
        hits.TYPE='pageview'
      ORDER BY
        1,
        2,
        3) )
  WHERE
    URL='/products/id1222894335'
  GROUP BY
    URL,
    PreviousURL) a
FULL OUTER JOIN EACH (
  SELECT
    URL,
    NextURL,
    COUNT(NextURL) NUMBER
  FROM (
    SELECT
      sessionId,
      TIME,
      URL,
      NUMBER,
      LEAD(URL) OVER (PARTITION BY sessionId ORDER BY TIME) NextURL
    FROM (
      SELECT
        sessionId,
        hits.TIME TIME,
        hits.pagePath URL,
        RANK() OVER (PARTITION BY sessionId ORDER BY hits.TIME ASC) NUMBER
      FROM
        [owox-demo:OWOXBI_Streaming.session_streaming_20160711]
      WHERE
        hits.TYPE='pageview'
      ORDER BY
        1,
        2,
        3))
  WHERE
    URL='/products/id1222894335'
  GROUP BY
    URL,
    NextURL) b
ON
  a.PreviousURL=b.NextURL
WHERE
  PreviousURL IS NOT NULL
  OR NextURL IS NOT NULL
ORDER BY
  3 DESC,
  4 DESC