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" 
  } 
]

❮ Dynamic Attribute Names Joins ❯