Simple MySQL Solution beats 100 %
\nSELECT\n\tsell_date,\n\tCOUNT(DISTINCT (product)) AS num_sold, \n\tGROUP_CONCAT(DISTINCT(product)) AS products \nFROM Activities \nGROUP BY sell_date \nORDER 
```\nSELECT\n\tsell_date,\n\tCOUNT(DISTINCT (product)) AS num_sold, \n\tGROUP_CONCAT(DISTINCT(product)) AS products \nFROM Activities \nGROUP BY sell_date \nORDER BY sell_date ASC;\n```\nEdit : As someone pointed out in the comments, we could use ```GROUP_CONCAT(DISTINCT(product) ORDER BY product ASC)``` to sort the products, but the above query works just as fine.
['MySQL']