SELECT
  *
FROM
  `river-island-clothing-co-ltd.12345678.ga_realtime_sessions_2*`
WHERE
  exportKey IN (
  SELECT
    exportKey
  FROM (
    SELECT
      exportKey,
      exportTimeUsec,
      MAX(exportTimeUsec) OVER (PARTITION BY visitKey) maxexportTimeUsec
    FROM
      `river-island-clothing-co-ltd.12345678.ga_realtime_sessions_2*`
    WHERE
      PARSE_DATE("%Y%m%d", date) = CURRENT_DATE())
  WHERE
    exportTimeUsec >= maxexportTimeUsec)