MS SQL SERVER Simple Solution
\nselect sell_date, \n    COUNT(product) as num_sold,\n    STRING_AGG(product,\',\') WITHIN GROUP (ORDER BY product) as products from\n    (select distinct sell
```\nselect sell_date, \n    COUNT(product) as num_sold,\n    STRING_AGG(product,\',\') WITHIN GROUP (ORDER BY product) as products from\n    (select distinct sell_date,product FROM Activities) Act\n    GROUP BY sell_date\n```
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