Скачать или смотреть LeetCode - 1204. Last Person to Fit in the Bus (SQL)

Welcome to the detailed solution and walkthrough for the SQL challenge 'Last Person to Fit in the Bus' from LeetCode.

Concepts Covered:
-- Aggregate Window Functions: Employing the SUM() function in a windowed fashion to cumulatively sum up values based on a specific order.
-- ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW: This specifies that the window starts at the first row of the result set and ends at the current row. As you progress row-by-row, the window extends to include the next row. It's useful for creating running totals or cumulative sums.

Additional information:
-- ROWS BETWEEN N PRECEDING AND M FOLLOWING: This means the window starts N rows before the current row and ends M rows after the current row. If you replace N or M with a specific integer value, you'll get that many rows before or after the current row included in the window.
-- ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING: This specifies the window starts at the current row and continues until the end of the result set.
-- ROWS UNBOUNDED PRECEDING: This indicates the window starts at the first row of the result set and only includes the current row.
-- ROWS UNBOUNDED FOLLOWING: This would indicate the window starts at the current row and ends at the last row of the result set. But note, it's uncommon to start at the current row and end at the last row without some specific preceding condition.
-- ROWS CURRENT ROW: This will only consider the current row. It's essentially a way to reset aggregates or computations for each row.
-- RANGE vs ROWS: In addition to ROWS, there's also RANGE, but it behaves differently. While ROWS looks at a fixed number of rows, RANGE considers the actual values. For example, RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW would include all rows where the value is the same as the current row's value. This can lead to differences in calculations, especially if there are duplicate values in your ordered column.

Whether you're prepping for interviews or refining your SQL skills, this solution will provide you with practical insights and a clearer understanding of some pivotal SQL techniques.

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