CODEWITHSUNDEEP
sortingarangodb
Loredra L
Loredra L

Reputation: 1553

ArangoDb Sort with Return Distinct skip over correct results and in wrong order

I have in a collection A 100k documents with ArangoDB 3.0. Each of them have a non-unique "group" properties which is an integer. I want to get all of them uniquely with the following query:

  FOR entry IN Collection
  FILTER entry.group!=null
  SORT entry.group ASC
  RETURN DISTINCT entry.group

The results skip over several group and sometimes in wrong order

[//Missing 1 here
  2,
  3,
  5,
  ...
  204,
  53,//Wrong order
  205,

Upvotes: 1

Views: 99

Answers (2)

peak
peak

Reputation: 116870

The following should circumvent the limitations of RETURN DISTINCT in earlier versions of ArangoDB and might also be more efficient:

FOR x IN (
    FOR entry IN Collection
      FILTER entry.group
      RETURN DISTINCT entry.group )
  SORT x ASC
  RETURN x

Upvotes: 1

peak
peak

Reputation: 116870

From the manual:

Note: the order of results was undefined for RETURN DISTINCT until before ArangoDB 3.3. Starting with ArangoDB 3.3, RETURN DISTINCT will not change the order of the results it is applied on.

Upvotes: 2

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