/* Standard SQL */
SELECT DISTINCT
  user_id,
  session_date,
  /* Case when logic to 'clean up' the data into 0 or 1 values */
  CASE
    WHEN global_consent_status IS NULL THEN '0'
    WHEN global_consent_status='false' THEN '0'
  ELSE global_consent_status 
  END AS global_consent_status  
/* Selecting from the table we've just made */
FROM (
  SELECT
    /* Unnesting the custom dimension part of the GA export and returning only values in slot 5 (which we know from the GA interface is User ID) */
    (SELECT MAX(IF(index = 5,value,NULL)) FROM UNNEST(customDimensions)) AS user_id,
    date AS session_date,
    /* Unnesting the custom dimension field and returning only values in slot 22 (which we know from the GA interface is the Global Consent Status) */
    (SELECT MAX(IF(index = 22,value,NULL)) FROM UNNEST(customDimensions)) AS global_consent_status
  FROM
  /* Selecting from the GA export tables where the data is coming from */
    `hbo-nordic-bigquery-1322.134556033.ga_sessions_*`
  /* Date range of the query */
  WHERE _TABLE_SUFFIX BETWEEN '20181201' AND '20181212')
WHERE
  /* Only return rows with distinct user_id values */
  user_id IS NOT NULL AND user_id != ''
ORDER BY user_id