CREATE TABLE category (id NUMBER, business_id VARCHAR2, category_name VARCHAR2)
CREATE TABLE review (rid NUMBER, business_id VARCHAR2, user_id VARCHAR2, rating FLOAT, text TEXT, year NUMBER, month VARCHAR2)
CREATE TABLE business (bid NUMBER, business_id VARCHAR2, name VARCHAR2, full_address VARCHAR2, city VARCHAR2, latitude VARCHAR2, longitude VARCHAR2, review_count NUMBER, is_open NUMBER, rating FLOAT, state VARCHAR2)
CREATE TABLE tip (tip_id NUMBER, business_id VARCHAR2, text TEXT, user_id VARCHAR2, likes NUMBER, year NUMBER, month VARCHAR2)
CREATE TABLE user (uid NUMBER, user_id VARCHAR2, name VARCHAR2)
CREATE TABLE checkin (cid NUMBER, business_id VARCHAR2, count NUMBER, day VARCHAR2)
CREATE TABLE neighborhood (id NUMBER, business_id VARCHAR2, neighborhood_name VARCHAR2)

how many users reviewed ' Sushi Too ' in Pittsburgh
SELECT COUNT(DISTINCT (user.name)) FROM business, review, user WHERE business.city = 'Pittsburgh' AND business.name = 'Sushi Too' AND review.business_id = business.business_id AND user.user_id = review.user_id
SELECT COUNT(DISTINCT "user"."name") FROM "business" JOIN "review" ON "business"."business_id" = "review"."business_id" JOIN "user" ON "review"."user_id" = "user"."user_id" WHERE "business"."city" = 'Pittsburgh' AND "business"."name" = 'Sushi Too'