CODEWITHSUNDEEP
rethinkdb
Kludge
Kludge

Reputation: 2835

RethinkDB: How can I perform several aggregation operations by running only one query?

For a table with the following results (not necessarily records with ids): [{time: 4, votes: 10}, {time: 6, votes: 3} ... ]

How can I get the following result (or similar): {average_time: 5, total_votes: 13} by running only ONE query and not two?

Upvotes: 1

Views: 344

Answers (2)

Masatoshi
Masatoshi

Reputation: 197

try this :)

r.object(
    'average_time',
    r.table('data')('time').avg(),
    'total_votes',
    r.table('data')('votes').sum()
)

Upvotes: 1

neumino
neumino

Reputation: 4353

You can use reduce to perform multiple aggregations. This should work

r.table('data').map(function(doc) {
  return {
    total_votes: doc("votes"),
    total_time: doc("times"),
    count: 1
  }
}).reduce(function(left, right) {
  return {
    total_votes: left("total_votes").add(right("total_votes")),
    total_time: left("total_time").add(right("total_time")),
    count: left("count").add(right("count"))
  }
}).map(function(result) {
  return {
    total_votes: result("total_votes"),
    average_time: result("total_time").div(result("count"))
  }
})

Upvotes: 1

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