How many businesses are there in Phoenix city? Find the percentage of businesses in Phoenix city in the total city.
percentage = MULTIPLY(DIVIDE(SUM(city = 'Phoenix' END), COUNT(category_id)), 1.0);
SELECT SUM(CASE WHEN T3.city LIKE 'Phoenix' THEN 1 ELSE 0 END) AS "num" , CAST(SUM(CASE WHEN T3.city LIKE 'Phoenix' THEN 1 ELSE 0 END) AS REAL) * 100 / COUNT(T3.city) FROM Business_Categories AS T1 INNER JOIN Categories AS T2 ON T1.category_id = T2.category_id INNER JOIN Business AS T3 ON T1.business_id = T3.business_id