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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

Python How to Create Function

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In Python, you can define and call the function. Once done, you can call it later from the other program. I have shared the structure of it. And, I have added the three rules of it; useful for interviews. Structure of Function Structure of Function Rules to Create a Function A function definition is executable. The body will have the code to perform the task you wish. You can assign default parameter values. 1. Key Elements. You will find here three key elements of the Python function. Here you can read the parameter vs argument differences . Name of a function. It can be any valid identifier. It should be meaningful, and it should convey the work it will do. Parameter. These should be separated with command and should be in the parentheses following the name of the function. The parameters are input to function. It can have any parameters. Body of the function. The function body can contain code that implements the task to be performed by it. 2. Sample Function. Python Example. def