Projections and Filters
Returning unaltered documents
To return three complete documents from collection users, the following query can be used:
FOR u IN users
LIMIT 0, 3
RETURN u
[
{
"_id" : "users/229886047207520",
"_rev" : "229886047207520",
"_key" : "229886047207520",
"active" : true,
"id" : 206,
"age" : 31,
"gender" : "f",
"name" : "Abigail"
},
{
"_id" : "users/229886045175904",
"_rev" : "229886045175904",
"_key" : "229886045175904",
"active" : true,
"id" : 101,
"age" : 36,
"name" : "Fred",
"gender" : "m"
},
{
"_id" : "users/229886047469664",
"_rev" : "229886047469664",
"_key" : "229886047469664",
"active" : true,
"id" : 208,
"age" : 29,
"name" : "Mary",
"gender" : "f"
}
]
Note that there is a LIMIT
clause but no SORT
clause. In this case it is not guaranteed
which of the user documents are returned. Effectively the document return order is unspecified
if no SORT
clause is used, and you should not rely on the order in such queries.
Projections
To return a projection from the collection users use a modified RETURN
instruction:
FOR u IN users
LIMIT 0, 3
RETURN {
"user" : {
"isActive" : u.active ? "yes" : "no",
"name" : u.name
}
}
[
{
"user" : {
"isActive" : "yes",
"name" : "John"
}
},
{
"user" : {
"isActive" : "yes",
"name" : "Anthony"
}
},
{
"user" : {
"isActive" : "yes",
"name" : "Fred"
}
}
]
Filters
To return a filtered projection from collection users, you can use the
FILTER
keyword. Additionally, a SORT
clause is used to have the result
returned in a specific order:
FOR u IN users
FILTER u.active == true && u.age >= 30
SORT u.age DESC
LIMIT 0, 5
RETURN {
"age" : u.age,
"name" : u.name
}
[
{
"age" : 37,
"name" : "Sophia"
},
{
"age" : 37,
"name" : "John"
},
{
"age" : 36,
"name" : "Emma"
},
{
"age" : 36,
"name" : "Fred"
},
{
"age" : 34,
"name" : "Madison"
}
]