Get Custom Dimension information using Standard SQL

/* 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