How can I get the lowest values in a MongoDB collection?

Question

I have a MongoDB collection called product which has the following documents as seen below.

{
    \"product\" : \"Milk\",
    \"barcode\" : 12345,
    \"pric         


        

Answer 1

You need to $group your documents by "price". From there, you $sort them by "_id" in ascending order and use $limit to return the first document which nothing other than the document with the minimum value.

db.products.aggregate([ 
    { "$group": { 
        "_id": "$price", 
        "docs": { "$push": "$$ROOT" } 
    }},
    { "$sort": { "_id": 1 } }, 
    { "$limit": 1 } 
])

which produces something like:

{
    "_id" : 100,
    "docs" : [
        {
            "_id" : ObjectId("574a161b17569e552e35edb5"),
            "product" : "Milk",
            "barcode" : 12345,
            "price" : 100,
            "store" : "BestBuy"
        },
        {
            "_id" : ObjectId("574a161b17569e552e35edb6"),
            "product" : "Milk",
            "barcode" : 12345,
            "price" : 100,
            "store" : "WalMart"
        }
    ]
}