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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

Messages in Kafka the Types and Details

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A message, also called a record, is the basic piece of data flowing through Kafka. Messages are how Kafka represents your data. Kafka producer Vs. consumer messages Kafka is an intermediate server that receives a message from a producer and sends them to the consumer. Here is a set of 10 Kafka Interview Questions. Kafka message format Each message has a timestamp, a value, and an optional key. Custom headers can be used if desired as well.  A simple example of a message could be something like the following: the machine with host ID “1234567” (a message key) failed with the message “Alert: Machine Failed” (a message value) at “2020-10-02T10:34:11.654Z” (a message timestamp). Here is Kafka's flowchart for dummies. Kafka record The above image shows probably the most important and common parts of a message that users deal with directly. Each key and value can interact in its own specific ways to serialize or deserialize its data. Now that we have a record, how do we let Kafka know ab