Why You NEED to Master CROSS JOINS (Data Interview) ⚔️ | LeetCode 1280 (SQL vs. Pandas)

In this video, we solve "Students and Examinations" (LeetCode 1280), a tricky Data Science interview question asked at companies like Amazon.

The Challenge: How do you report students who attended zero exams? If you just use a standard GROUP BY, those students disappear!

The Solution: I show you how to generate a Cartesian Product (Master List) first to ensure every student/subject pair exists before counting.

SQL Solution: Using CROSS JOIN followed by a LEFT JOIN.
Pandas Solution: Using .merge(how='cross') and filling NaN values.

⏱️ Timestamps:
0:00 - Intro
0:53 - SQL Solution
2:53 - Pandas Solution

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Видео Why You NEED to Master CROSS JOINS (Data Interview) ⚔️ | LeetCode 1280 (SQL vs. Pandas) канала DataHead Girl