groupConcat (Aggregate Function)

This function aggregates the received events by concatenating the keys in those events using a separator, e.g.,a comma (,) or a hyphen (-), and returns the concatenated key string.

Syntax

<STRING> str:groupConcat(<STRING> key)
<STRING> str:groupConcat(<STRING> key, <STRING> ...)
<STRING> str:groupConcat(<STRING> key, <STRING> separator, <BOOL> distinct)
<STRING> str:groupConcat(<STRING> key, <STRING> separator, <BOOL> distinct, <STRING> order)

Query Parameters

Name	Description	Default Value	Possible Data Types	Optional	Dynamic
key	The string that needs to be aggregated.		STRING	No	Yes
separator	The separator that separates each string key after concatenating the keys.	,	STRING	Yes	Yes
distinct	This is used to only have distinct values in the concatenated string that is returned.	false	BOOL	Yes	Yes
order	This parameter accepts ASC or DESC strings to sort the string keys in either ascending or descending order respectively.	No order	STRING	Yes	Yes

Example 1

from InputStream WINDOW SLIDING_TIME(5 min)
select str:groupConcat("key") as groupedKeys
input OutputStream;

When we input events having values for the key as 'A', 'B', 'S', 'C', 'A', it returns "A,B,S,C,A" to the OutputStream.

Example 2

from InputStream WINDOW SLIDING_TIME(5 min)
select groupConcat("key","-",true,"ASC") as groupedKeys
input OutputStream;

When we input events having values for the key as 'A', 'B', 'S', 'C', 'A', specify the seperator as hyphen and choose the order to be ascending, the function returns "A-B-C-S" to the OutputStream.