db.ClassMembers.insertMany([ { "ClassID":"CL0001", "StudentID":"S000001", "DateFrom":"2015-09-01" }, { "ClassID":"CL0002", "StudentID":"S000002", "DateFrom":"2015-09-01" }]);db.Scores.insertMany([{ "StudentID":"S000001", "TestID":"T000001", "Scores":[{ "Course":"Chinese", "Score":80 },{ "Course":"Maths", "Score":70 },{ "Course":"English", "Score":75 }]},{ "StudentID":"S000002", "TestID":"T000001", "Scores":[{ "Course":"Chinese", "Score":70 },{ "Course":"Maths", "Score":80 },{ "Course":"English", "Score":82 }]}]);db.ClassMembers.aggregate([ { $match: {ClassID: 'CL0001'} }, { $lookup: { from: "Scores", localField: "StudentID", foreignField: "StudentID", as: "ScoresDocs" } }, { $match : { "ScoresDocs.TestID" : 'T000001' }}, { $project: { _id: 0, ClassID: 1, ScoresDocs: 1}}, { $unwind: '$ScoresDocs'}, { $unwind: '$ScoresDocs.Scores'}, { $match: {'ScoresDocs.Scores.Course':'Chinese'}}])
//最后一步
将数据从对象列取出来地址：https://docs.mongodb.com/master/reference/operator/aggregation/replaceRoot/#pipe._S_replaceRoot
转载于:https://www.cnblogs.com/luoliangfei/p/7426657.html
