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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

15 awesome Java Interview Questions to know

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Java interview is one of the tough interviews for developers coming from other technologies. So I have given very basic interview questions they asked. Really awesome to know these questions. 1. What is JVM? Why is Java called the ‘Platform Independent Programming Language’? JVM, or the Java Virtual Machine, is an interpreter that accepts ‘Bytecode’ and executes it. Java has been termed as a ‘Platform Independent Language’ as it primarily works on the notion of ‘compile once, run everywhere’. Here’s a sequential step establishing the Platform independence feature in Java: The Java Compiler outputs Non-Executable Codes called ‘Bytecode’. Bytecode is a highly optimized set of a computer instruction which could be executed by the Java Virtual Machine (JVM). The translation into Bytecode makes a program easier to be executed across a wide range of platforms since all we need is a JVM designed for that particular platform. JVMs for various platforms might vary in configuration, those they w