Explaining data structures to the Business Intelligence team

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Query

select qr_code.qrd_id,
qr_code.folder,
qr_code.title,
coalesce(NULLIF(city, ''), NULLIF(village, '')) as city_or_village,
user_request.*,
access_control.email
from user_request
join qr_code on user_request.qr_code_id = qr_code.id
left outer join access_control on access_control.folder=qr_code.folder;