MySQL 9.1 Release Notes
MySQL supports window functions that, for each row from a query,
perform a calculation using rows related to that row. The
following sections discuss how to use window functions, including
descriptions of the OVER
and
WINDOW
clauses. The first section provides
descriptions of the nonaggregate window functions. For
descriptions of the aggregate window functions, see
Section 14.19.1, “Aggregate Function Descriptions”.
For information about optimization and window functions, see Section 10.2.1.21, “Window Function Optimization”.