How many Yelp_Business under the category of "Food" are good for kids?
under the category of "Food" refers to category_name = 'Food'; are good for kids refers to attribute_name = 'Good for Kids' and attribute_value = 'true'
SELECT COUNT(T3.stars) 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_Attributes AS T4 ON T3.business_id = T4.business_id INNER JOIN Attributes AS T5 ON T4.attribute_id = T5.attribute_id WHERE T1.category_name LIKE 'Food' AND T5.attribute_name LIKE 'Good for Kids' AND T4.attribute_value LIKE 'TRUE'