Group_Concat function | Easy to Understand | MySQL Solution
\nSELECT\n    sell_date,\n    COUNT(DISTINCT product) AS "num_sold",\n    GROUP_CONCAT(\n        DISTINCT product\n        ORDER BY\n            product\n    ) 
```\nSELECT\n    sell_date,\n    COUNT(DISTINCT product) AS "num_sold",\n    GROUP_CONCAT(\n        DISTINCT product\n        ORDER BY\n            product\n    ) AS "products"\nFROM\n    activities\nGROUP BY\n    sell_date;\n```
['MySQL']