SQL
Window Functions
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DuckDB supports [window functions](https://en.wikipedia.org/wiki/Window_function_(SQL)), which can use multiple rows to calculate a value for each row.
Window functions are [blocking operators](#docs:guides:performance:how_to_tune_workloads::blocking-operators), i.e., they require their entire input to be buffered, making them one of the most memory-intensive operators in SQL.  
Window function are available in SQL since [SQL:2003](https://en.wikipedia.org/wiki/SQL:2003) and are supported by major SQL database systems.