How to find something from an array in mongo - mongodb

Question

{
"_id" : ObjectId("586aac4c8231ee0b98458045"),
"store_code" : NumberInt(10800),
"counter_name" : "R.N.Electric",
"address" : "314 khatipura road",
"locality" : "Khatipura Road (Jhotwara)",
"pincode" : NumberInt(302012),
"town" : "JAIPUR",
"gtm_city" : "JAIPUR",
"sales_office" : "URAJ",
"owner_name" : "Rajeev",
"owner_mobile" : "9828024073",
"division_mapping" : [//this contains only 1 element in every doc
{
"dvcode" : "cfc",
"dc" : "trade",
"beatcode" : "govindpura",
"fos" : {
"_id" : ObjectId("586ab8318231ee0b98458843"),
"loginid" : "9928483483",
"name" : "Arpit Gupta",
"division" : [
"cfc",
"iron"
],
"sales_office" : "URAJ", //office
"gtm_city" : "JAIPUR" //city
},
"beat" : {
"_id" : ObjectId("586d372b39f64316b9c3cbd7"),
"division" : {
"_id" : ObjectId("5869f8b639f6430fe4edee2a"),
"clientdvcode" : NumberInt(40),
"code" : "cfc",
"name" : "Cooking & Fabric Care",
"project_code" : "usha-fos",
"client_code" : "usha",
"agent_code" : "v5global"
},
"beatcode" : "govindpura",
"sales_office" : "URAJ",
"gtm_city" : "JAIPUR",
"active" : true,
"agency_code" : "v5global",
"client_code" : "USHA_FOS",
"proj_code" : "usha-fos",
"fos" : {
"_id" : ObjectId("586ab8318231ee0b98458843"),
"loginid" : "9928483483",
"name" : "Arpit Gupta",
"division" : [
"cfc",
"iron"
],
"sales_office" : "URAJ",
"gtm_city" : "JAIPUR"
}
}
}
],
"distributor_mail" : "sunil.todi#yahoo.in",
"project_code" : "usha-fos",
"client_code" : "usha",
"agent_code" : "v5global",
"distributor_name" : "Sundeep Electrical"
}
I am having only 1 element in division_mapping's array and I want to find those documents whose dc in division_mapping is trade.
I have tried following:
"division_mapping":{$elemMatch:{$eq:{"dc":"trade"}}}})
Dont know what I am doing wrong.
//Maybe I have to unwind the array but is there any other way?

Answer 1

According to MongoDB documentation
The $elemMatch operator matches documents that contain an array
field with at least one element that matches all the specified query
criteria.
According to above mentioned description to retrieve only documents whose dc in division_mapping is trade please try executing below mentioned query
db.collection.find({division_mapping:{$elemMatch:{dc:'trade'}}})