For the FROM clause, specify one or more event streams or named windows as the input.
Syntax:
from eventStreamDefinition [as name] [unidirectional] [retain-union | retain-intersection]
[,eventStreamDefinition [as name]] [, ...]
The eventStreamDefinition is a filter-based event stream definition or a pattern-based event stream definition. For AS, a name (alias) can be attached to a stream definition.
Refer to "1.2.11 JOIN Clause" for information on UNIDIRECTIONAL.
Syntax:
eventStreamName [( filterCondition )] [.view] [.view]
The eventStreamName is an event type name, an event stream name specified in the INSERT INTO clause of a different complex event processing statement, or the name of a named window.
For the filterCondition specification, use properties and operators, functions (except for the aggregate function), or similar, to describe the condition. Commas (,) can be used in a filterCondition with the same meaning as the AND logical operator.
In addition, event expiry policy specifications (if a data window view) and data derivations can be specified by specifying a view, as described at "1.7 Views".
If more than one view is specified, the common parts of those views are retained by default (same as the RETAIN-INTERSECTION specification). The union parts of multiple views can be retained by specifying RETAIN-UNION.
Syntax:
pattern [ patternExpression ] [.view] [.view]
Pattern-based event streams are specified by describing a patternExpression inside square brackets, "[" and "]", following the PATTERN keyword. A view can also be specified for a pattern in the same way as for filter-based event stream definitions.
Refer to "1.4 Patterns" for information on how to describe a patternExpression.
