Here is my original query:
SELECT EventType, InitiatedAt, COUNT(*) as cnt FROM HS_IHE_ATNA_Repository.Aggregation WHERE EventType = 'LOGIN' AND LocalDateTime > '2016-02-16 11:00:00' GROUP BY EventType, InitiatedAt
This gives me data like this:
InterSystems Caché is a multi-model DBMS and application server. See more details here.