根據條件查詢 MongoDB 記錄?
要根據條件查詢 MongoDB,使用 find() 並設定條件。我們建立一個包含文件的集合 −
> db.demo708.insertOne({"Name":"John",Marks:54}); { "acknowledged" : true, "insertedId" : ObjectId("5ea702e4d346dcb074dc6f33") } > db.demo708.insertOne({"Name":"Chris",Marks:35}); { "acknowledged" : true, "insertedId" : ObjectId("5ea702e6d346dcb074dc6f34") } > db.demo708.insertOne({"Name":"David",Marks:45}); { "acknowledged" : true, "insertedId" : ObjectId("5ea702ebd346dcb074dc6f35") } > db.demo708.insertOne({"Name":"Bob",Marks:40}); { "acknowledged" : true, "insertedId" : ObjectId("5ea702fad346dcb074dc6f36") }
藉助 find() 方法從集合中顯示所有文件 −
> db.demo708.find();
這將生成以下輸出 −
{ "_id" : ObjectId("5ea702e4d346dcb074dc6f33"), "Name" : "John", "Marks" : 54 } { "_id" : ObjectId("5ea702e6d346dcb074dc6f34"), "Name" : "Chris", "Marks" : 35 } { "_id" : ObjectId("5ea702ebd346dcb074dc6f35"), "Name" : "David", "Marks" : 45 } { "_id" : ObjectId("5ea702fad346dcb074dc6f36"), "Name" : "Bob", "Marks" : 40 }
以下是根據條件查詢 MongoDB 記錄的查詢 −
> db.demo708.find({Marks:{$gt:40}});
這將生成以下輸出 −
{ "_id" : ObjectId("5ea702e4d346dcb074dc6f33"), "Name" : "John", "Marks" : 54 } { "_id" : ObjectId("5ea702ebd346dcb074dc6f35"), "Name" : "David", "Marks" : 45 }
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