maropu commented on a change in pull request #28220: [SPARK-31390][SQL][DOCS] Document Window Function in SQL Syntax Section URL: https://github.com/apache/spark/pull/28220#discussion_r408792539
########## File path: docs/sql-ref-syntax-qry-window.md ########## @@ -19,4 +19,222 @@ license: | limitations under the License. --- -**This page is under construction** +### Description + +Similarly to aggregate functions, window functions operate on a group of rows. However, unlike aggregate functions, window functions perform aggregation without reducing, calculating a return value for each row in the group. Window functions are useful for processing tasks such as calculating a moving average, computing a cumulative, or accessing the value of rows given the relative position of the current row. Spark SQL supports three types of window functions: Review comment: `window functions perform aggregation without reducing, calculating a return value for each row in the group.` is not clear. This means `window functions do not compute a single aggregated value. Instead, they can generate multiple aggregated values for each group`? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
