How to Filter Specific Fields from MongoDB Documents using the Mongo-Go-Driver?

Filtering Fields from MongoDB Documents with Mongo-Go-Driver

To filter specific fields from a MongoDB document using Mongodb-Go-Driver, the findopt.Projection option can be utilized. However, in your provided code, the issue arises due to the field _id within the fields struct being unexported (starting with a lowercase letter).

Revised Solution:

To resolve this, the field name should be exported (starting with an uppercase letter) and utilize struct tags to map it to the MongoDB _id field. The updated code:

type fields struct {
    ID int `bson:"_id"`
}

Projection using Projection Option:

To perform a query with projection, use the options.FindOne().SetProjection(projection) method, where projection represents the desired fields to retrieve.

Updated Code:

projection := fields{
    ID: 0,
}
result := staCon.collection.FindOne(
    nil, filter, options.FindOne().SetProjection(projection)).Decode(s)

Alternative Using bson.Document:

Alternatively, a bson.Document can be used as the projection:

projection := bson.NewDocument(
    bson.EC.Int32("_id", 0),
)
result := staCon.collection.FindOne(
    nil, filter, options.FindOne().SetProjection(projection)).Decode(s)

Using these approaches, you can filter specific fields from MongoDB documents, suppressing unnecessary fields such as _id if desired.

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