MongoDB: $elemMatch

Question

I\'m trying to use $elemMatch to find an object in an array. I imported the following data into a collection named trails:

{ \"Copper\"         


        

Answer 1

$elemmatch(query) returns all rows in a array when there is atleast one row matching the query criteria.

$elemMatch(projection) returns only the first row of all the matching rows when used as projection.

You don't need elemMatch for your case as it is only single criteria.

db.trails.find({"Copper.name": { "Spaulding Bowl" } })

Try as below which uses the elemMatch projection variation.

db.trails.find({}, {"Copper": { $elemMatch: { "name" : "Spaulding Bowl" } }  } )