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Legal Studies查詢 MongoDB 中陣列元素具有特定值的檔案？
為了匹配 MongoDB 中的檔案，請使用 $elemMatch。我們首先建立一個包含檔案的集合 −
> db.demo15.insertOne({"Details":[{"Score":56},{"Score":78}]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e0f7806d7df943a7cec4fab")
}
> db.demo15.insertOne({"Details":[{"Score":86},{"Score":86}]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e0f7817d7df943a7cec4fac")
}
> db.demo15.insertOne({"Details":[{"Score":97},{"Score":85}]});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e0f7823d7df943a7cec4fad")
}以下是使用 find() 方法顯示集合中所有檔案時的查詢 −
> db.demo15.find();
這將產生以下輸出 −
{ "_id" : ObjectId("5e0f7806d7df943a7cec4fab"), "Details" : [ { "Score" : 56 }, { "Score" : 78 } ] }
{ "_id" : ObjectId("5e0f7817d7df943a7cec4fac"), "Details" : [ { "Score" : 86 }, { "Score" : 86 } ] }
{ "_id" : ObjectId("5e0f7823d7df943a7cec4fad"), "Details" : [ { "Score" : 97 }, { "Score" : 85 } ] }以下是查詢陣列中的所有元素都具有特定值的檔案的查詢 −
> db.demo15.find({
... "Details.Score" : {
... $exists : true
... },
... "Details" : {
... $not : {
... $elemMatch : {
... "Score" : {
... $ne : 86
... }
... }
... }
... }
... });這將產生以下輸出 −
{ "_id" : ObjectId("5e0f7817d7df943a7cec4fac"), "Details" : [ { "Score" : 86 }, { "Score" : 86 } ] }
更新於： 01-Apr-2020
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