Database
[{finish:false},{finish:true},{finish:true},{finish:false},{finish:true}]
Query
db.collection.aggregate([{$group:{_id:null,documents:{$push:"$$ROOT"}}},{$set:{finish:{$size:{$filter:{input:"$documents",cond:{$eq:["$$this.finish",true]}}}},non_finish:{$size:{$filter:{input:"$documents",cond:{$eq:["$$this.finish",false]}}}}}}])