MS SQL / Using STRING_AGG
\nwith t as (\n    select distinct * from Activities)\n\nselect \n     sell_date\n    ,count(1) as num_sold\n    ,string_agg(product,\',\') within group (order 
```\nwith t as (\n    select distinct * from Activities)\n\nselect \n     sell_date\n    ,count(1) as num_sold\n    ,string_agg(product,\',\') within group (order by product) as products\nfrom t\ngroup by sell_date\norder by sell_date\n```
['MS SQL Server']