arangodb AQL aggregate result and return object

Question

I want to aggregate some ratings in AQL. The below query

FOR l IN locations
COLLECT rating = l.rating WITH COUNT INTO ratings
RETURN {[rating]: ratings}

returns and array of object:

[
  {
    "Good": 4639
  },
  {
    "Bad": 517
  },
  {
    "So so": 1017
  }
]

what I need is one object like:

[
  {
    "Good": 4639,
    "Bad": 517,
    "So so": 1017
  }
]

Answer 1

You can use MERGE(doc) to achieve the desired result:

RETURN MERGE (
  FOR l IN locations
    COLLECT rating = l.rating WITH COUNT INTO ratings
    RETURN {[rating]: ratings}
)

Tested with my test collection (using prop2 rather than rating):

[
  {
    "baz": 1,
    "other": 2
  }
]

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