SQL 50:Leetcode 1731 - The Number of Employees Which Report to Each Employee(InterviewPrepEssential)

Описание: Master one of the most common SQL interview questions: analyzing hierarchical data!

In this video, we break down LeetCode problem 1731, "The Number of Employees Which Report to Each Employee." This problem is a fantastic exercise in using SQL's most powerful techniques to navigate organizational structures and count direct reports.

What You Will Learn:
*The Power of Self-Joins:* Learn how and why to join an employee table to itself (a self-join) to correctly link employees to their respective managers.
*Effective Grouping and Aggregation:* Use the `GROUP BY` clause with the `COUNT()` aggregate function to determine the exact number of direct reports for each manager.
*Handling Nulls with LEFT JOIN:* We’ll explore how to ensure that only true managers (those who actually appear in the `reports_to` column) are included in the results, ensuring a clean and correct output.
*Sorting Data:* Finalizing the query with proper ordering to meet the exact problem requirements.

If you are preparing for a data analyst, data scientist, or software engineering interview, understanding this type of relationship query is essential.

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*🧑‍💻 Resources:*
Link to Problem 1731 on LeetCode: https://leetcode.com/problems/the-num...
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