为了精确匹配,请在MongoDB $in()中设置要匹配的值。首先让我们创建一个包含文档的集合-
> db.demo422.insertOne({"Name":"Chris","Marks":34}); { "acknowledged" : true, "insertedId" : ObjectId("5e73a4059822da45b30346e1") } > db.demo422.insertOne({"Name":"Chris","Marks":56}); { "acknowledged" : true, "insertedId" : ObjectId("5e73a40a9822da45b30346e2") } > db.demo422.insertOne({"Name":"David","Marks":78}); { "acknowledged" : true, "insertedId" : ObjectId("5e73a4149822da45b30346e3") } > db.demo422.insertOne({"Name":"Sam","Marks":45}); { "acknowledged" : true, "insertedId" : ObjectId("5e73a41e9822da45b30346e4") } > db.demo422.insertOne({"Name":"David","Marks":89}); { "acknowledged" : true, "insertedId" : ObjectId("5e73a4239822da45b30346e5") }
在find()
方法的帮助下显示集合中的所有文档-
> db.demo422.find();
这将产生以下输出-
{ "_id" : ObjectId("5e73a4059822da45b30346e1"), "Name" : "Chris", "Marks" : 34 } { "_id" : ObjectId("5e73a40a9822da45b30346e2"), "Name" : "Chris", "Marks" : 56 } { "_id" : ObjectId("5e73a4149822da45b30346e3"), "Name" : "David", "Marks" : 78 } { "_id" : ObjectId("5e73a41e9822da45b30346e4"), "Name" : "Sam", "Marks" : 45 } { "_id" : ObjectId("5e73a4239822da45b30346e5"), "Name" : "David", "Marks" : 89 }
以下是查询以获取与多个文档字段完全匹配的记录-
> db.demo422.find({'$and': [{'Name': {'$in': ['Chris', 'David']}, 'Marks': {'$in': [34,89]}}]});
这将产生以下输出-
{ "_id" : ObjectId("5e73a4059822da45b30346e1"), "Name" : "Chris", "Marks" : 34 } { "_id" : ObjectId("5e73a4239822da45b30346e5"), "Name" : "David", "Marks" : 89 }