leetcode - SQL 50 (1)

1378. Replace Employee ID With The Unique Identifier

https://leetcode.com/problems/replace-employee-id-with-the-unique-identifier/?envType=study-plan-v2&envId=top-sql-50

SELECT unique_id , name
FROM employees A LEFT join employeeUNI B  ON A.id=B.id

1068. Product Sales Analysis I

https://leetcode.com/problems/product-sales-analysis-i/submissions/972445640/?envType=study-plan-v2&envId=top-sql-50

SELECT product_name, year,price
FROM sales A JOIN product B USING (product_id)

1581. Customer Who Visited but Did Not Make Any Transactions

https://leetcode.com/problems/customer-who-visited-but-did-not-make-any-transactions/description/?envType=study-plan-v2&envId=top-sql-50

SELECT customer_id, count(A.visit_id) count_no_trans
FROM visits A LEFT JOIN transactions B ON A.visit_id = B.visit_id
WHERE transaction_id IS NULL
GROUP BY customer_id