public async Task GroupsAndCounts()
{
// :code-block-start: agg_group
var groupStage =
new BsonDocument("$group",
new BsonDocument
{
{ "_id", "$type" },
{ "count", new BsonDocument("$sum", 1) }
});
var sortStage = new BsonDocument("$sort",
new BsonDocument("_id", 1));
var aggResult = await plantsCollection.AggregateAsync(groupStage, sortStage);
foreach (var item in aggResult)
{
var id = item["_id"];
var count = item["count"];
Console.WriteLine($"Plant type: {id}; count: {count}");
}
// :code-block-end:
Assert.AreEqual(PlantType.Annual.ToString(), aggResult[0]["_id"].AsString);
Assert.AreEqual(PlantType.Perennial.ToString(), aggResult[1]["_id"].AsString);
Assert.AreEqual(3, aggResult[0]["count"].AsInt32);
Assert.AreEqual(2, aggResult[1]["count"].AsInt32);
// :code-block-start: agg_group_alt
var groupStep = BsonDocument.Parse(@"
{
$group: {
_id: '$type',
count: {
$sum: 1
}
}
}
");
var sortStep = BsonDocument.Parse("{$sort: { _id: 1}}");
aggResult = await plantsCollection.AggregateAsync(groupStep, sortStep);
foreach (var item in aggResult)
{
var id = item["_id"];
var count = item["count"];
Console.WriteLine($"Id: {id}, Count: {count}");
}
// :code-block-end:
Assert.AreEqual(PlantType.Annual.ToString(), aggResult[0]["_id"].AsString);
Assert.AreEqual(PlantType.Perennial.ToString(), aggResult[1]["_id"].AsString);
Assert.AreEqual(3, aggResult[0]["count"].AsInt32);
Assert.AreEqual(2, aggResult[1]["count"].AsInt32);
}