Inbuilt Aggregate Functions

Aggregate functions are used to perform operations such as sum on aggregated set of events through a window. Usage of a aggregate function is as follows.

@info(name = 'query1') 
from cseEventStream#window.timeBatch(1 sec) 
select symbol, sum(price) as price
insert into resultStream;

Following are the supported inbuilt aggregate functions of Siddhi.

Sum

Syntax	`<long\|double> sum(<int\|long\|double\|float> arg)`
Extension Type	Aggregate Function
Description	Calculates the sum for all the events.
Parameter	The value that needs to be summed.
Return Type	Returns long if the input parameter type is `int` or `long`, and returns double if the input parameter type is `float` or `double.`
Examples	`sum(20`) returns the sum of 20s as a long value for each event arrival and expiry. `sum(temp)` returns the sum of all temp attributes based on each event arrival and expiry.

Average

Syntax	`<double> avg(<int\|long\|double\|float> arg)`
Extension Type	Aggregate Function
Description	Calculates the average for all the events.
Parameter	`arg`: The value that need to be averaged.
Return Type	Returns the calculated average value as a double.
Example	`avg(temp)` returns the average temp value for all the events based on their arrival and expiry.

Maximum

Syntax	`<int\|long\|double\|float> max(<int\|long\|double\|float> arg)`
Extension Type	Aggregate Function
Description	Returns the maximum value for all the events.
Parameter	`arg`: The value that needs to be compared to find the maximum value.
Return Type	Returns the maximum value in the same data type as the input.
Example	`max(temp)` returns the maximum temp value recorded for all the events based on their arrival and expiry.

Minimum

Syntax	`<int\|long\|double\|float> min(<int\|long\|double\|float> arg)`
Extension Type	Aggregate Function
Description	Returns the minimum value for all the events.
Parameter	`arg`: The value that needs to be compared to find the minimum value.
Return Type	Returns the minimum value in the same type as the input.
Example	`min(temp)` returns the minimum temp value recorded for all the events based on their arrival and expiry.

Count

Syntax	`<long> count()`
Extension Type	Aggregate Function
Description	Returns the count of all the events.
Return Type	Returns the event count as a long.
Example	`count()` returns the count of all the events.

Standard Deviation

Syntax	`<double> stddev(<int\|long\|double\|float> arg)`
Extension Type	Aggregate Function
Description	Returns the calculated standard deviation for all the events.
Parameter	`arg`: The value that should be used to calculate the standard deviation.
Return Type	Returns the calculated standard deviation value as a double.
Example	`stddev(temp)` returns the calculated standard deviation of temp for all the events based on their arrival and expiry.

Distinct Count

Syntax	`<long> distinctcount(<int\|long\|double\|float\|string> arg)`
Extension Type	Aggregate Function
Description	Aggregate function to returns the count of distinct occurances of a given arg
Parameter	`arg`: The value that should be counted
Return Type	Returns the count of distinct occurances of given arg
Example	distinctcount(pageID) for following output will return 3. "WEB_PAGE_1" "WEB_PAGE_1" "WEB_PAGE_2" "WEB_PAGE_3" "WEB_PAGE_1" "WEB_PAGE_2"

Forever Maximum

Syntax	<int\|long\|double\|float> maxForever (<int\|long\|double\|float> arg)
Extension Type	Aggregate Function
Description	Attribute aggregator to store maximum value for a given attribute throughout the lifetime of the query regardless of any windows in-front.
Parameter	`arg`: The value that needs to be compared to find the maximum value.
Return Type	Returns the maximum value in the same data type as the input.
Example	`maxForever(temp)` returns the maximum temp value recorded for all the events throughout the lifetime of query

Forever Minimum

Syntax	<int\|long\|double\|float> minForever (<int\|long\|double\|float> arg)
Extension Type	Aggregate Function
Description	Attribute aggregator to store minimum value for a given attribute throughout the lifetime of the query regardless of any windows in-front.
Parameter	`arg`: The value that needs to be compared to find the minimum value.
Return Type	Returns the minimum value in the same data type as the input.
Example	`minForever(temp)` returns the minimum temp value recorded for all the events throughout the lifetime of query