CREATE TABLE category (id NUMBER, business_id VARCHAR2, category_name VARCHAR2)
CREATE TABLE user (uid NUMBER, user_id VARCHAR2, name 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 review (rid NUMBER, business_id VARCHAR2, user_id VARCHAR2, rating FLOAT, text TEXT, year NUMBER, month VARCHAR2)
CREATE TABLE neighborhood (id NUMBER, business_id VARCHAR2, neighborhood_name VARCHAR2)
CREATE TABLE checkin (cid NUMBER, business_id VARCHAR2, count NUMBER, day VARCHAR2)
CREATE TABLE tip (tip_id NUMBER, business_id VARCHAR2, text TEXT, user_id VARCHAR2, likes NUMBER, year NUMBER, month VARCHAR2)

Find users whose average review rating is below 3
SELECT user.name FROM review, user WHERE user.user_id = review.user_id GROUP BY user.name HAVING AVG(review.rating) < 3
SELECT "user"."name" FROM "review" JOIN "user" ON "review"."user_id" = "user"."user_id" GROUP BY "user"."name" HAVING AVG("review"."rating") < 3