Query results

Result sets

The result of an AQL query is an array of values. The individual values in the result array may or may not have a homogeneous structure, depending on what is actually queried.

For example, when returning data from a collection with inhomogeneous documents (the individual documents in the collection have different attribute names) without modification, the result values will as well have an inhomogeneous structure. Each result value itself is a document:

FOR u IN users
    RETURN u

[
  { "id": 1, "name": "John", "active": false },
  { "age": 32, "id": 2, "name": "Vanessa" },
  { "friends": [ "John", "Vanessa" ], "id": 3, "name": "Amy" }
]

However, if a fixed set of attributes from the collection is queried, then the query result values will have a homogeneous structure. Each result value is still a document:

FOR u IN users
    RETURN { "id": u.id, "name": u.name }

[
  { "id": 1, "name": "John" },
  { "id": 2, "name": "Vanessa" },
  { "id": 3, "name": "Amy" }
]

It is also possible to query just scalar values. In this case, the result set is an array of scalars, and each result value is a scalar value:

FOR u IN users
    RETURN u.id

[ 1, 2, 3 ]

If a query does not produce any results because no matching data can be found, it will produce an empty result array:

[ ]