How many taverns failed in July 2010?
tavern refers to facility_type = 'Tavern'; failed refers to results = 'Fail'; in July 2010 refers to inspection_date like '2010-07%'
SELECT COUNT(DISTINCT T1.license_no) FROM establishment AS T1 INNER JOIN inspection AS T2 ON T1.license_no = T2.license_no WHERE strftime('%Y-%m', T2.inspection_date) = '2010-07' AND T2.results = 'Fail' AND T1.facility_type = 'Restaurant'