with account_session_ste as (
SELECT 
*
FROM `table`
where exists(select 1 from unnest(hits) h 
            where regexp_contains(h.page.hostname, r'signin.account.gov.uk'))
and _table_suffix = FORMAT_DATE('%Y%m%d', DATE_SUB(CURRENT_DATE(), INTERVAL 4 DAY))
)
-- group by 1,2)
select 
fullVisitorId AS user_id,
hits.page.hostname as hostname,   
hits.page.pagePath as pagePath,
hits.hitNumber as hit_number 
-- *
from account_session_ste, unnest(hits) as hits