Solving SQL problems is like solving a mystery with multiple suspects🕵️. The key is to find the most active suspect, or in this case, parent, by using different methods of investigation. Whether it’s by filtering out the inactive parents or grouping the data to find the max status, there are always multiple ways to crack the case!🔍✨
Key Takeaways
This article will provide multiple solutions to a common SQL interview problem. It will demonstrate different methods for solving the problem and the most efficient solution will be highlighted.
Solution 1️⃣
In the first solution, we start by filtering the active parents from the input table. We then group the data by parent ID and extract the active parents based on the status. After this, we fetch the inactive parents by excluding the active ones using a subquery.
Solution 2️⃣
Moving on to solution two, we use window functions to partition the records based on parent ID and order them by status. We then fetch the first record for each parent ID to get all the active parents.
Solution 3️⃣
Solution three is similar to solution two, except we use a subquery instead of a common table expression (CTE) to achieve the same result. This highlights the flexibility of different approaches to solving the problem.
Solution 4️⃣
In solution four, we use outer joins to fetch all parents and then filter the active parents. This method allows us to identify the inactive parents and categorize them accordingly.
Solution 5️⃣
Solution five involves using the UNION clause to merge the records of active and inactive parents from the input table. We handle the case sensitivity of the status column and then combine the results using the UNION clause.
Solution 6️⃣
Finally, in solution six, we use the MAX function to group the data by parent ID and fetch the maximum status for each parent. This provides a straightforward and efficient solution to the problem.
By providing multiple solutions to the SQL interview problem, this article aims to demonstrate the variety of approaches that can be used to tackle the same problem. Each solution offers a different perspective and highlights the versatility of SQL query writing. If you found this article helpful, give it a thumbs up and share it with your friends. Thank you for watching!
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