MongoDB finds the minimum or maximum value based on the metrics in the subkey

Suppose you have such data in the students collection:

{"_id": 1, "name": "Aurelia Menendez", "scores": [{"Type" : "Exam", "Score": 60.06045071030959}, {"T                        Ype ":" Quiz "," Score ": 52.79790691903873}, {                        "Type": "Homework", "Score": 71.76133439165544}, { "Type": "Homework", "Score": 34.85718117893772}]},{"_id                        ": 3," "Name": "Bao ziglar", "scores": [{"type": "Exam",                        "Score": 71.64343899778332}, {"type": "Quiz", "Score": 24.80221293650313}, {"Type": "Homewor                     K ",   "Score": 1.694720653897219}, {"type": "Homework",        "Score": 42.26147058804812}]},{"_id": 2, "name": "Corliss Zuk",                 "Scores": [{"type": "Exam", "Score": 67.03077096065002 }, {"type": "Quiz", "Score": 6.30185167783 5235}, {"type": "Homework", "score": 20.18  160621941858}, {"type": "Homework", "score" : 66.28344683278382}]}

To find out the minimum value of each student's performance, use the following statement:

db.students.aggregate([{$project: {minScore: {$min: "$scores.score"}}}])

The statement inside minScore is equal to an alias and can be used for other. The results are as follows:

{ "_id" : 1, "minScore" : 34.85718117893772 }{ "_id" : 3, "minScore" : 1.694720653897219 }{ "_id" : 2, "minScore" : 6.301851677835235 }{ "_id" : 4, "minScore" : 19.21886443577987 }{ "_id" : 5, "minScore" : 10.53058536508186 }{ "_id" : 7, "minScore" : 42.48780666956811 }{ "_id" : 6, "minScore" : 16.58341639738951 }{ "_id" : 8, "minScore" : 14.63969941335069 }{ "_id" : 9, "minScore" : 12.47568017314781 }{ "_id" : 0, "minScore" : 1.463179736705023 }{ "_id" : 12, "minScore" : 14.78936520432093 }{ "_id" : 13, "minScore" : 78.18795058912879 }{ "_id" : 14, "minScore" : 13.66179556675781 }{ "_id" : 11, "minScore" : 15.81264595052612 }{ "_id" : 16, "minScore" : 7.772386442858281 }{ "_id" : 15, "minScore" : 3.311794422000724 }{ "_id" : 18, "minScore" : 62.12870233109035 }{ "_id" : 17, "minScore" : 31.15090466987088 }{ "_id" : 10, "minScore" : 19.31113429145131 }{ "_id" : 19, "minScore" : 0.6578497966368002 }

MongoDB finds the minimum or maximum value based on the metrics in the subkey