Which Yelp_Business in Arizona gets the most number of reviews?
Arizona refers to state = 'AZ'; gets the most number of reviews refers to max(count(Reviews.business_id))
SELECT T1.user_id FROM Reviews AS T1 INNER JOIN Business AS T2 ON T1.business_id = T2.business_id WHERE T2.state LIKE 'AZ' GROUP BY T1.user_id ORDER BY COUNT(T1.user_id) DESC LIMIT 1