CREATE TABLE problems (product_id VARCHAR)
CREATE TABLE product (product_name VARCHAR, product_id VARCHAR)

Find the top 3 products which have the largest number of problems?
SELECT T2.product_name FROM problems AS T1 JOIN product AS T2 ON T1.product_id = T2.product_id GROUP BY T2.product_name ORDER BY COUNT(*) DESC LIMIT 3
SELECT "T2"."product_name" FROM "problems" AS "T1" JOIN "product" AS "T2" ON "T1"."product_id" = "T2"."product_id" GROUP BY "T2"."product_name" ORDER BY COUNT(*) DESC NULLS LAST LIMIT 3