Correct Solution...
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 MySQL query statement below:-\nSELECT product_id,"store1" as store,store1 as price\nFROM Products\nWHERE store1 IS NOT NULL\nUNION SELECT product_id,"store2",store2\nFROM Products\nWHERE store2 IS NOT NULL\nUNION SELECT product_id,"store3",store3\nFROM Products\nWHERE store3 IS NOT NULL;\n```
['MySQL']