Time-based windows have a KEEP clause that defines how long the window will keep rows, and whether or not these rows will expire from the window one at a time, or all in a group.
Sliding Time-Based Windows
A sliding time-based window retains a variable number of rows, depending on how many rows have arrived within the specified interval.
Jumping Time-Based Windows
A jumping time-based window adds rows to a window for a fixed interval and then expires all of the old rows at the same time when the end of the interval is reached. Provides the syntax for a jumping time-based window.