db={members:[{"_id":{"$oid":"60dca71f0394f430c8ca296d"},"church":"60dbb265a75a610d90b45c6b","name":"Julio Verne Cerqueira"},{"_id":{"$oid":"60dca71f0394f430c8ca29a8"},"name":"Ryan Steel Oliveira","church":"60dbb265a75a610d90b45c6c"}],churchies:[{"_id":{"$oid":"60dbb265a75a610d90b45c6c"},"name":"Saint Antoine Hill","active":true},{"_id":{"$oid":"60dbb265a75a610d90b45c6b"},"name":"Jackeline Hill","active":true}]}

db.members.aggregate([{"$lookup":{"from":"churchies","let":{searchId:{"$toObjectId":"$church"}},"pipeline":[{$match:{$expr:{$eq:["$_id","$$searchId"]}}},{$project:{name:1}}],"as":"church"}},{"$unwind":"$church"},{$project:{_id:1,church:"$church.name",name:1}},{"$sort":{"church":1,"name":1}}])