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 category (id NUMBER, business_id VARCHAR2, category_name VARCHAR2)
CREATE TABLE user (uid NUMBER, user_id VARCHAR2, name VARCHAR2)
CREATE TABLE tip (tip_id NUMBER, business_id VARCHAR2, text TEXT, user_id VARCHAR2, likes NUMBER, year NUMBER, month VARCHAR2)

Find the users who have given tips on Pet Groomers
SELECT user.name FROM business, category, tip, user WHERE category.business_id = business.business_id AND category.category_name = 'Pet Groomers' AND tip.business_id = business.business_id AND user.user_id = tip.user_id
SELECT "user"."name" FROM "business" JOIN "category" ON "business"."business_id" = "category"."business_id" AND "category"."category_name" = 'Pet Groomers' JOIN "tip" ON "business"."business_id" = "tip"."business_id" JOIN "user" ON "tip"."user_id" = "user"."user_id"