MongoDb aggregate and group by two fields depending on values -

MongoDb aggregate and group by two fields depending on values -

i want aggregate on collection type given. if type foo want grouping field author, if type bar want grouping user.

all should happen in 1 query.

example data:

{ "_id": 1, "author": { "somefield": "abc", }, "type": "foo" } { "_id": 2, "author": { "somefield": "abc", }, "type": "foo" } { "_id": 3, "user": { "somefield": "abc", }, "type": "bar" }

this user field existing if type bar.

so that... tried express $or.

function () { var results = db.vote.aggregate( [ { $or: [ { { $match : { type : "foo" } }, { $group : { _id : "$author", sumauthor : {$sum : 1} } } }, { { $match : { type : "bar" } }, { $group : { _id : "$user", sumuser : {$sum : 1} } } } ] } ] ); homecoming results; }

does have solution this?

i think can done

db.c.aggregate([{ $group : { _id : { $cond : [{ $eq : [ "$type", "foo"] }, "author", "user"] }, sum : { $sum : 1 } } }]);

mongodb group mongodb-query aggregation-framework