Query to Find Distinct Products Sold by Date:
Selects the sell_date, counts the number of distinct products sold (num_sold), and concatenates the distinct product names for each date.
Groups the results by sell_date and orders them by sell_date.
Query to List Products Ordered in a Period:
Selects product names and their total units ordered within the period '2020-02-01' to '2020-02-29' for products that have a total of at least 100 units ordered.
A subquery calculates the total units ordered per product within the specified period and filters out those with fewer than 100 units.
The main query joins the result of the subquery with the Products table to retrieve the product names.