Table: Prices
+---------------+---------+ +| Column Name | Type | ++---------------+---------+ +| product_id | int | +| start_date | date | +| end_date | date | +| price | int | ++---------------+---------+ +(product_id, start_date, end_date) is the primary key (combination of columns with unique values) for this table. +Each row of this table indicates the price of the product_id in the period from start_date to end_date. +For each product_id there will be no two overlapping periods. That means there will be no two intersecting periods for the same product_id. ++ +
+ +
Table: UnitsSold
+---------------+---------+ +| Column Name | Type | ++---------------+---------+ +| product_id | int | +| purchase_date | date | +| units | int | ++---------------+---------+ +This table may contain duplicate rows. +Each row of this table indicates the date, units, and product_id of each product sold. ++ +
+ +
Write a solution to find the average selling price for each product. average_price should be rounded to 2 decimal places.
Return the result table in any order.
+ +The result format is in the following example.
+ ++
Example 1:
+ +Input: +Prices table: ++------------+------------+------------+--------+ +| product_id | start_date | end_date | price | ++------------+------------+------------+--------+ +| 1 | 2019-02-17 | 2019-02-28 | 5 | +| 1 | 2019-03-01 | 2019-03-22 | 20 | +| 2 | 2019-02-01 | 2019-02-20 | 15 | +| 2 | 2019-02-21 | 2019-03-31 | 30 | ++------------+------------+------------+--------+ +UnitsSold table: ++------------+---------------+-------+ +| product_id | purchase_date | units | ++------------+---------------+-------+ +| 1 | 2019-02-25 | 100 | +| 1 | 2019-03-01 | 15 | +| 2 | 2019-02-10 | 200 | +| 2 | 2019-03-22 | 30 | ++------------+---------------+-------+ +Output: ++------------+---------------+ +| product_id | average_price | ++------------+---------------+ +| 1 | 6.96 | +| 2 | 16.96 | ++------------+---------------+ +Explanation: +Average selling price = Total Price of Product / Number of products sold. +Average selling price for product 1 = ((100 * 5) + (15 * 20)) / 115 = 6.96 +Average selling price for product 2 = ((200 * 15) + (30 * 30)) / 230 = 16.96 ++