Скачать или смотреть Syntax and Components of Window Functions

@genaiexp Understanding the syntax of SQL window functions is key to mastering their use. A window function is composed of the function itself and the OVER() clause. The OVER() clause is crucial because it defines the window or the set of rows the function should operate on. Within the OVER() clause, you can specify an ORDER BY clause, which determines the order of rows the function processes. This is essential for functions like ROW_NUMBER or RANK, where the order impacts the result. The PARTITION BY clause, which we'll explore in detail later, allows you to divide your result set into partitions and apply the window function to each partition independently. This can be particularly useful for segmenting data by categories, such as customer regions or product types, to perform localized calculations. Mastering these components will enable you to craft powerful queries that extract meaningful insights from your data.