Ordering by Fields

Legacy SQL

SELECT
     CONCAT(fullVisitorId, ".", STRING(visitId)) AS Session_ID,
     totals.pageviews AS Pageviews
FROM   
     [google.com:analytics-bigquery:LondonCycleHelmet.ga_sessions_20130910]
ORDER BY
     Pageviews DESC
LIMIT 5

Standard SQL

SELECT
     CONCAT(fullVisitorId, ".", CAST(visitId AS STRING)) AS Session_ID,
     totals.pageviews AS Pageviews
FROM   
     'google.com:analytics-bigquery.LondonCycleHelmet.ga_sessions_20130910'
ORDER BY
     Pageviews DESC
LIMIT 5