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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 Story behind Mainframe to Cloud Real Journey

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Mainframe to CLOUD: Mainframe computing took off in the 1950s and gained much prominence throughout the 1960s. Corporations such as IBM (International Business Machines), Univac, DEC (Digital Equipment Corporation), and Control Data Corporation started developing powerful mainframe systems. Gettyimage.in These mainframe systems mainly carried out number-crunching for scientists and engineers. The main programming language used was Fortran. Then in the 1960s, the notion of database systems was conceived and corporations developed database systems based on the network and hierarchical data models. The database applications at that time were written mainly in COBOL. Cloud Vs Mainframe In the 1970s, corporations such as DEC created the notion of mini-computers. An example is DEC's VAX machine. These machines were much smaller than the mainframe systems. Around that time, terminals were developed. This way, programmers did not have to go to computing centers and use punch cards