first (Window)
This is a window that holds only the first set of unique events according to the unique key parameter. When a new event arrives with a key that is already in the window, that event is not processed by the window.
Syntax
unique:first(<INT|LONG|FLOAT|BOOL|DOUBLE|STRING> unique.key)
unique:first(<INT|LONG|FLOAT|BOOL|DOUBLE|STRING> unique.key, <INT|LONG|FLOAT|BOOL|DOUBLE|STRING> ...)
Query Parameters
| Name | Description | Default Value | Possible Data Types | Optional | Dynamic |
|---|---|---|---|---|---|
| unique.key | The attribute that should be checked for uniqueness. If there is more than one parameter to check for uniqueness, it can be specified as an array separated by commas. | INT LONG FLOAT BOOL DOUBLE STRING | No | Yes |
Example 1
CREATE STREAM LoginEvents (timeStamp long, ip string);
insert into UniqueIps
from LoginEvents WINDOW UNIQUE:first(ip);
This returns the first set of unique items that arrive from the LoginEvents stream, and returns them to the UniqueIps stream. The unique events are only those with a unique value for the ip attribute.