Problem
Table: Orders
+---------------+---------+ | Column Name | Type | +---------------+---------+ | order_id | int | | customer_id | int | | order_date | date | | item_id | varchar | | quantity | int | +---------------+---------+ (ordered_id, item_id) is the primary key (combination of columns with unique values) for this table. This table contains information on the orders placed. order_date is the date item_id was ordered by the customer with id customer_id.
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Table: Items
+---------------------+---------+ | Column Name | Type | +---------------------+---------+ | item_id | varchar | | item_name | varchar | | item_category | varchar | +---------------------+---------+ item_id is the primary key (column with unique values) for this table. item_name is the name of the item. item_category is the category of the item.
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You are the business owner and would like to obtain a sales report for category items and the day of the week.
Write a solution to report how many units in each category have been ordered on each day of the week.
Return the result table ordered by category
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The result format is in the following example.
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Example 1:
Input: Orders table: +------------+--------------+-------------+--------------+-------------+ | order_id | customer_id | order_date | item_id | quantity | +------------+--------------+-------------+--------------+-------------+ | 1 | 1 | 2020-06-01 | 1 | 10 | | 2 | 1 | 2020-06-08 | 2 | 10 | | 3 | 2 | 2020-06-02 | 1 | 5 | | 4 | 3 | 2020-06-03 | 3 | 5 | | 5 | 4 | 2020-06-04 | 4 | 1 | | 6 | 4 | 2020-06-05 | 5 | 5 | | 7 | 5 | 2020-06-05 | 1 | 10 | | 8 | 5 | 2020-06-14 | 4 | 5 | | 9 | 5 | 2020-06-21 | 3 | 5 | +------------+--------------+-------------+--------------+-------------+ Items table: +------------+----------------+---------------+ | item_id | item_name | item_category | +------------+----------------+---------------+ | 1 | LC Alg. Book | Book | | 2 | LC DB. Book | Book | | 3 | LC SmarthPhone | Phone | | 4 | LC Phone 2020 | Phone | | 5 | LC SmartGlass | Glasses | | 6 | LC T-Shirt XL | T-Shirt | +------------+----------------+---------------+ Output: +------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+ | Category | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday | Sunday | +------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+ | Book | 20 | 5 | 0 | 0 | 10 | 0 | 0 | | Glasses | 0 | 0 | 0 | 0 | 5 | 0 | 0 | | Phone | 0 | 0 | 5 | 1 | 0 | 0 | 10 | | T-Shirt | 0 | 0 | 0 | 0 | 0 | 0 | 0 | +------------+-----------+-----------+-----------+-----------+-----------+-----------+-----------+ Explanation: On Monday (2020-06-01, 2020-06-08) were sold a total of 20 units (10 + 10) in the category Book (ids: 1, 2). On Tuesday (2020-06-02) were sold a total of 5 units in the category Book (ids: 1, 2). On Wednesday (2020-06-03) were sold a total of 5 units in the category Phone (ids: 3, 4). On Thursday (2020-06-04) were sold a total of 1 unit in the category Phone (ids: 3, 4). On Friday (2020-06-05) were sold 10 units in the category Book (ids: 1, 2) and 5 units in Glasses (ids: 5). On Saturday there are no items sold. On Sunday (2020-06-14, 2020-06-21) were sold a total of 10 units (5 +5) in the category Phone (ids: 3, 4). There are no sales of T-shirts.