SQL Window Functions
An Introduction With Examples
SQL window functions are a powerful feature that allow users to perform calculations across a set of rows that are related to the current row. This feature is incredibly useful for performing complex calculations such as running totals, moving averages, and ranking without the need to create temporary tables or write multiple queries. In this article, we will explore several SQL window functions and demonstrate how to use them through practical examples.
Introduction to Window Functions
Window functions operate on a set of rows and return a single value for each row from the underlying query. They are called window functions because they perform calculations across a “window” of rows related to the current row. This window can be defined in various ways, such as all rows in the table, rows within a particular partition, or rows between two boundaries.
Key Window Functions
ROW_NUMBER(): Assigns a unique number to each row starting from 1.
RANK(): Assigns a rank to each row within a partition with gaps; rows with the same values…
