FHIR Chat · CQL grouping equivalent · implementers

Stream: implementers

Topic: CQL grouping equivalent

Erik Smith (Feb 08 2022 at 16:21):

I want to express a query to find the claim provider with the most frequent visits for a member in CQL, not specific to FHIR. This would be straightforward if CQL had a SQL GROUP BY. It's unclear how I can accomplish this with aggregate. Any Ideas?

Bryn Rhodes (Feb 08 2022 at 17:15):

We didn't add a group by or having clause, but both of those are just short-hands. The long-hand for count of observations by category, for example, is:

define ObservationCountsByCategory:
  [Observation] O
    return {
      category: O.category,
      numberOfObservations: Count([Observation] InnerO where InnerO.category ~ O.category)
    }

Erik Smith (Feb 08 2022 at 19:26):

This is nice. I was thinking that you would want the outer source O need to be distinct observations by category , or just a a distinct category list, for the counts to work, but maybe that is optional since the result of this query will be distinct?

Bryn Rhodes (Feb 08 2022 at 19:51):

Right, the result will be distinct.

Last updated: Apr 12 2022 at 19:14 UTC