Choose correct queries with different
count methods available in MongoDB aggregation framework?

Question

Accepted Answer

db.persons.aggregate([{
$group: { _id: "$customer.gender" } },{ $count: "genderCount"}]);

Accepted Answer

db.persons.aggregate([]).toArray().length;

Answer

db.persons.aggregate([]).length([1]);

Answer

db.persons.aggregate([
{ $group: { _id: "$customer.gender", count: { $sum: 1 } } }]);

Answer

db.persons.aggregate([]).size();

Answer

db.persons.aggregate([{$count:"total"}]);

Answer

db.persons.aggregate([]).itcount();

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