How many "Good for Kids" Yelp_Businesses are open everyday of the week?
Good for Kids refers to attribute_name = 'Good for Kids'and attribute_value = 'true'; open everyday refers to day_id between 1 and 7
SELECT COUNT(T1.business_id) FROM Business_Hours AS T1 INNER JOIN Days AS T2 ON T1.day_id = T2.day_id INNER JOIN Business_Attributes AS T3 ON T1.business_id = T3.business_id INNER JOIN Attributes AS T4 ON T4.attribute_id = T4.attribute_id WHERE T2.day_id IN (1, 2, 3, 4, 5, 6, 7) AND T4.attribute_name = 'Good for Kids' AND T3.attribute_value = 'true'