+-------------+---------+
|Column Name |Type|+-------------+---------+
| sell_date | date || product | varchar |+-------------+---------+
There isnoprimarykey (columnwithuniquevalues) for this table. It may contain duplicates.
Eachrowof this tablecontains the product name and the date it was sold in a market.
Write a solution to find for each date the number of different products sold and their names.
The sold products names for each date should be sorted lexicographically.
Input:
Activities table:+------------+------------+| sell_date | product |+------------+------------+|2020-05-30| Headphone ||2020-06-01| Pencil ||2020-06-02| Mask ||2020-05-30| Basketball ||2020-06-01| Bible ||2020-06-02| Mask ||2020-05-30| T-Shirt |+------------+------------+Output:
+------------+----------+------------------------------+| sell_date | num_sold | products |+------------+----------+------------------------------+|2020-05-30|3| Basketball,Headphone,T-shirt ||2020-06-01|2| Bible,Pencil ||2020-06-02|1| Mask |+------------+----------+------------------------------+Explanation:
For 2020-05-30, Sold items were(Headphone, Basketball, T-shirt), we sort them lexicographically and separate them by a comma.For 2020-06-01, Sold items were(Pencil, Bible), we sort them lexicographically and separate them by a comma.For 2020-06-02, the Sold item is(Mask), we just return it.