Database

db={"results":[{"_id":"5eaeab6b2b9f246693a65659","points":14,"kilogramms":14,"place":14,"sector":"A","competition":"5eaeaa5448580765da33165a","user":"5ead24956ee84737c5910d06"},{"_id":"5eaec018784ea96aa7daeebe","points":23,"kilogramms":23,"place":12,"sector":"A","competition":"5eaeaa5448580765da33165a","user":"5eaebf3471aab66a84ae01a4"},{"_id":"5eaec028784ea96aa7daeebf","points":12,"kilogramms":12,"place":14,"sector":"A","competition":"5eaeaa5448580765da33165a","user":"5eaebf7f784ea96aa7daeeba"},{"_id":"5eaec03c784ea96aa7daeec0","points":30,"kilogramms":34,"place":1,"sector":"B","competition":"5eaeaa5448580765da33165a","user":"5eaebfa7784ea96aa7daeebb"},{"_id":"5eaec04c784ea96aa7daeec1","points":21,"kilogramms":20,"place":2,"sector":"B","competition":"5eaeaa5448580765da33165a","user":"5eaebfd4784ea96aa7daeebc"},{"_id":"5eaec05a784ea96aa7daeec2","points":13,"kilogramms":13,"place":3,"sector":"B","competition":"5eaeaa5448580765da33165a","user":"5eaebff5784ea96aa7daeebd"}],"users":[{"_id":"5ead24956ee84737c5910d06","name":"User1","email":"user1_email","phone":"user1_phone",},{"_id":"5eaebf3471aab66a84ae01a4","name":"User2","email":"user2_email","phone":"user2_phone",},{"_id":"5eaebf7f784ea96aa7daeeba","name":"User3","email":"user3_email","phone":"user3_phone",},{"_id":"5eaebfa7784ea96aa7daeebb","name":"User4","email":"user4_email","phone":"user4_phone",},{"_id":"5eaebfd4784ea96aa7daeebc","name":"User5","email":"user5_email","phone":"user1_phone",},{"_id":"5eaebff5784ea96aa7daeebd","name":"User6","email":"user6_email","phone":"user6_phone",},]}

Query

db.results.aggregate([{$match:{competition:"5eaeaa5448580765da33165a"},},{$project:{points:1,kilogramms:1,sector:1,user:1,competition:1,place:1,},},{$sort:{kilogramms:-1,},},{$lookup:{from:"users",localField:"user",foreignField:"_id",as:"user"}},{$addFields:{user:{$arrayElemAt:["$user",0]}}},{$group:{_id:"$sector",res:{$push:"$$ROOT"},},},])

Result