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To search the array of object in MongoDB, you can use $elemMatch operator. This operator allows us to search for more than one component from an array object.
MongoDB provides the find() that is used to find multiple values or documents from the collection. The find() method returns a cursor of the result set and prints all the documents. To find the multiple values, we can use the aggregation operations that are provided by MongoDB itself.
Use the Array Index to Query for a Field in the Embedded Document. Using dot notation, you can specify query conditions for field in a document at a particular index or position of the array. The array uses zero-based indexing. When querying using dot notation, the field and index must be inside quotation marks.
The right way is:
db.users.find({awards: {$elemMatch: {award:'National Medal', year:1975}}})
$elemMatch allows you to match more than one component within the same array element.
Without $elemMatch mongo will look for users with National Medal in some year and some award in the year 1975, but not for users with National Medal in 1975.
See MongoDB $elemMatch Documentation for more info. See Read Operations Documentation for more information about querying documents with arrays.
Use $elemMatch to find the array of a particular object
db.users.findOne({"_id": id},{awards: {$elemMatch: {award:'Turing Award', year:1977}}})
as explained in above answers Also, to return only one field from the entire array you can use projection into find. and use $
db.getCollection("sizer").find(
{ awards: { $elemMatch: { award: "National Medal", year: 1975 } } },
{ "awards.$": 1, name: 1 }
);
will be return
{
_id: 1,
name: {
first: 'John',
last: 'Backus'
},
awards: [
{
award: 'National Medal',
year: 1975,
by: 'NSF'
}
]
}
You can do this in two ways:
ElementMatch - $elemMatch (as explained in above answers)
db.users.find({ awards: { $elemMatch: {award:'Turing Award', year:1977} } })
Use $and with find
db.getCollection('users').find({"$and":[{"awards.award":"Turing Award"},{"awards.year":1977}]})
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