MySQL Solution for Rearrange Products Table Problem
Intuition\n Describe your first thoughts on how to solve this problem. \nThe intuition behind the solution is to rearrange the data in the Products table to tra
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\nThe intuition behind the solution is to rearrange the data in the Products table to transform it into a result table with rows in the format (product_id, store, price).\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\nThe query consists of three SELECT statements combined using the UNION operator. Each SELECT statement retrieves the product_id, the store name as a string literal, and the price from the corresponding store column. The WHERE clause is used to exclude rows where the price is null in each store column.\n\nThe result will be a table with rows in the format (product_id, store, price), where each row represents a product available in a store with its corresponding price. The result table will include all products available in any of the stores, and the rows can be in any order.\n\nIf there are duplicate rows in the original Products table (same product_id with the same non-null price in multiple store columns), the UNION operator will remove the duplicates from the result table.\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\nThe time complexity of this query is dependent on the size of the Products table, as it needs to scan each row to check the availability of the product in each store. Therefore, the time complexity is O(n), where n is the number of rows in the table.\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\nThe space complexity is also dependent on the number of rows in the Products table. The query will generate a result table with rows for each product available in any of the stores. If there are m distinct products available in the stores, the space complexity is O(m).\n\n# Code\n```\n# Write your MySQL query statement below\nSELECT product_id, \'store1\' AS store, store1 AS price FROM Products WHERE store1 IS NOT NULL\nUNION\nSELECT product_id, \'store2\' AS store, store2 AS price FROM Products WHERE store2 IS NOT NULL\nUNION\nSELECT product_id, \'store3\' AS store, store3 AS price FROM Products WHERE store3 IS NOT NULL;\n\n```
['MySQL']