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Find MongoDB documents where elements of an array have a specific value?
To match documents in MongoDB, use $elemMatch. Let us first create a collection with documents −
> 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")
}Following is the query to display all documents from a collection with the help of find() method −
> db.demo15.find();
This will produce the following output −
{ "_id" : ObjectId("5e0f7806d7df943a7cec4fab"), "Details" : [ { "Score" : 56 }, { "Score" : 78 } ] }
{ "_id" : ObjectId("5e0f7817d7df943a7cec4fac"), "Details" : [ { "Score" : 86 }, { "Score" : 86 } ] }
{ "_id" : ObjectId("5e0f7823d7df943a7cec4fad"), "Details" : [ { "Score" : 97 }, { "Score" : 85 } ] }Here is the query to find documents where all elements of an array have a specific value −
> db.demo15.find({
... "Details.Score" : {
... $exists : true
... },
... "Details" : {
... $not : {
... $elemMatch : {
... "Score" : {
... $ne : 86
... }
... }
... }
... }
... });This will produce the following output −
{ "_id" : ObjectId("5e0f7817d7df943a7cec4fac"), "Details" : [ { "Score" : 86 }, { "Score" : 86 } ] }
Updated on: 01-Apr-2020
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