public abstract class Window extends Object
Window groups rows based on time or row-count intervals. It is a general way to group the elements, which is very helpful for both groupBy-aggregations and over-aggregations to compute aggregates on groups of elements.
Infinite streaming tables can only be grouped into time or row intervals. Hence window grouping is required to apply aggregations on streaming tables.
For finite batch tables, window provides shortcuts for time-based groupBy.
Constructor and Description |
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Window(Expression alias,
Expression timeField) |
Modifier and Type | Method and Description |
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Expression |
alias() |
Expression |
timeField() |
abstract LogicalWindow |
toLogicalWindow()
Converts an API class to a logical window for planning.
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public Window(Expression alias, Expression timeField)
public Expression alias()
public Expression timeField()
public abstract LogicalWindow toLogicalWindow()
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