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SQL Query: 3 Methods for Calculating Cumulative SUM

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SQL provides various constructs for calculating cumulative sums, offering flexibility and efficiency in data analysis. In this article, we explore three distinct SQL queries that facilitate the computation of cumulative sums. Each query leverages different SQL constructs to achieve the desired outcome, catering to diverse analytical needs and preferences. Using Window Functions (e.g., PostgreSQL, SQL Server, Oracle) SELECT id, value, SUM(value) OVER (ORDER BY id) AS cumulative_sum  FROM your_table; This query uses the SUM() window function with the OVER clause to calculate the cumulative sum of the value column ordered by the id column. Using Subqueries (e.g., MySQL, SQLite): SELECT t1.id, t1.value, SUM(t2.value) AS cumulative_sum FROM your_table t1 JOIN your_table t2 ON t1.id >= t2.id GROUP BY t1.id, t1.value ORDER BY t1.id; This query uses a self-join to calculate the cumulative sum. It joins the table with itself, matching rows where the id in the first table is greater than or

The best helpful hdfs file system commands (3 of 4)

dus- hadoop fs -dus PATH dus reports the sum of the file sizes in aggregate rather than individually. expunge- hadoop fs -expunge Empties the trash. If the trash feature is enabled, when a file is deleted, it is first moved into the temporary Trash/folder. The file will be permanently deleted from the Trash/folder only after user-configurable delay. get - hadoop -fs -get [-ignorecrc] [-crc] SRC LOCASDST Copies files to the local file system.