Aggregation functions

This section explains how to use and combine different aggregation functions in APL.

The table summarizes the aggregation functions available in APL. Use all these aggregation functions in the context of the summarize operator.

Function	Description
avg	Returns an average value across the group.
avgif	Calculates the average value of an expression in records for which the predicate evaluates to true.
count	Returns a count of the group without/with a predicate.
countif	Returns a count of rows for which the predicate evaluates to true.
dcount	Returns an estimate for the number of distinct values that are taken by a scalar an expressionession in the summary group.
dcountif	Returns an estimate of the number of distinct values of an expression of rows for which the predicate evaluates to true.
histogram	Returns a timeseries heatmap chart across the group.
make_list	Creates a dynamic JSON object (array) of all the values of an expression in the group.
make_list_if	Creates a dynamic JSON object (array) of an expression values in the group for which the predicate evaluates to true.
make_set	Creates a dynamic JSON array of the set of distinct values that an expression takes in the group.
make_set_if	Creates a dynamic JSON object (array) of the set of distinct values that an expression takes in records for which the predicate evaluates to true.
max	Returns the maximum value across the group.
maxif	Calculates the maximum value of an expression in records for which the predicate evaluates to true.
min	Returns the minimum value across the group.
minif	Returns the minimum of an expression in records for which the predicate evaluates to true.
percentile	Calculates the requested percentiles of the group and produces a timeseries chart.
percentileif	Calculates the requested percentiles of the field for the rows where the predicate evaluates to true.
rate	Calculates the rate of values in a group per second.
stdev	Calculates the standard deviation of an expression across the group.
stdevif	Calculates the standard deviation of an expression in records for which the predicate evaluates to true.
sum	Calculates the sum of an expression across the group.
sumif	Calculates the sum of an expression in records for which the predicate evaluates to true.
topk	calculates the top values of an expression across the group in a dataset.
variance	Calculates the variance of an expression across the group.
varianceif	Calculates the variance of an expression in records for which the predicate evaluates to true.