T-SQL STRING_AGG function used
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\n/* Write your T-SQL query statement below */\nselect \n  sell_date, \n  count(distinct product) as num_sold, \n  string_agg(product, \',\') WITHIN GROUP (ORDER BY product) as products\nfrom (select distinct sell_date, product from activities) ac\ngroup by ac.sell_date\n\n```
['MS SQL Server']