Computing Metrics
Use the optional select clause to compute metrics for your aggregated groups. Use these rules when constructing the select statement:
 Separate metric statements or distinct() function calls by commas.
 If you leave this control empty, IQL returns a count of all documents in each group.
The following metrics are available:
Metric  Syntax  Examples 

Simple metric name  metric  revenue 
Arithmetic expression of two metrics (+, , *, %) executed on each document. The divide operation (/) is executed in aggregate after everything else is computed. If you require a per document divide, use a reverse slash (\\). 
metric+metric metric\metric metric\*metric metric%metric metric/metric 
clicks/impressions revenueexpenses 
Function calls:

count() exp(metric,scalingFactor) floatscale(field,scale,offset) 
count() floatscale(float,10,5) multiplies each value in float by 10 and then adds 5 to each product. 
distinct()  distinct(field)  distinct(country) returns a count of distinct terms for the country field in each grouping. 
percentile()  percentile(field, N)  percentile(totaltime, 50) returns the median value of totaltime . 
Return a count of all of the documents that match the expression. Adding /count() returns the average. You must include "" around a string term. 
field="term" field=integer metric!=integer metric\<integer metric<=integer metric>integer metric>=integer lucene("luceneQueryStr") 
country="us" returns the number of documents with a value of us for country . clicks=1 returns the number of documents with a value of 1 for clicks .revenue>500 group="mobile"/count() 