Aggregates values and counts for specified fields. Aggregates have many use cases, they're particularly useful for grouping and displaying acceptable values for fields that are used in filters. For more information refer to Using Aggregates To Determine Acceptable Values For Filters.
Comma-separate multiple fields. Only the following fields may be aggregated; any other value is rejected with a 400 error:
type, subType, classification, source, address.state, address.area, address.city, address.neighborhood, school.districtName, school.schoolType, school.lowGrade, school.highGrade, school.schoolLevel, school.isCharterSchool, school.isMagnetSchool, school.isVirtualSchool, school.isPrivate, school.isJJFacility, school.privateSchoolAffiliation, school.giftedAndTalented, school.dualEnrollment, school.creditRecovery, school.singleSexClasses, school.apCourse, school.internationalBaccalaureate, school.corporalPunishment, school.interscholarAthletics, school.offersKindergarten, school.offersFullDayKindergarten, school.apEnrollment, school.expenditurePerStudent, school.isTitleISchool, school.isTitleISchoolwideSchool, school.privateHours, school.privateDays, school.privateHasLibrary, school.privateCoed, school.isAssigned