Write SQL query to solve given problem: How many businesses in Glendale city that are still running is opened from 8AM to 6PM?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T1.category_name) FROM Categories AS T1 INNER JOIN Business_Categories AS T2 ON T1.category_id = T2.category_id INNER JOIN Business AS T3 ON T2.business_id = T3.business_id INNER JOIN Business_Hours AS T4 ON T3.business_id = T4.business_id WHERE T3.city LIKE 'Glendale' AND T4.opening_time LIKE '8AM' AND T4.closing_time LIKE '6PM'