Simple solution using group_concat in mysql
\nselect sell_date, \n        count(distinct product) as num_sold,\n        group_concat(distinct product order by product) as products\nfrom Activities\ngroup 
```\nselect sell_date, \n        count(distinct product) as num_sold,\n        group_concat(distinct product order by product) as products\nfrom Activities\ngroup by sell_date\norder by sell_date\n```
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