Avoid nested queries

avoid_nested_queries.sql

-- avoid

SELECT
  products.product_name AS name,
  prices.product_price AS price

FROM
  (
    SELECT
      1 AS product_id,
      5 AS product_price
      
    UNION ALL
    
    SELECT
      2 AS product_id,
      4 AS product_price
  ) prices

JOIN
  (
    SELECT 
      1 AS product_id,
      'notebook' AS product_name
    
    UNION ALL
    
    SELECT
       2 AS product_id,
       'pen' AS product_name
   ) products ON products.product_id = prices.product_id