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SQL Anywhere 10.0.1 » SQL Anywhere Server - SQL Usage » OLAP Support » Window functions

Window functions Next Page

Defining a window

SQL windowing extensions allow you to configure the bounds of a window, as well as the partitioning and ordering of the input rows. Logically, as part of the semantics of computing the result of a query specification, partitions are created after the groups defined by the GROUP BY clause are created, but before the evaluation of the final SELECT list and the query's ORDER BY clause. Because window partitioning follows a GROUP BY operator, the result of any aggregate function, such as SUM, AVG, or VARIANCE, is available to the computation done for a partition. Hence, windows provide another opportunity to perform grouping and ordering operations in addition to a query's GROUP BY and ORDER BY clauses.

When you define the window over which a window function operates, you specify one or more of the following:

Sizing the window
Defining a window inline, or using a WINDOW clause