When attempting to retrieve a document by its _id field, you may encounter an issue where the returned value is empty. One potential cause is incorrect handling of the _id's ObjectID type.
In the provided code snippet, the _id is represented using a bson.RawValue, which is a generic type for holding BSON data without any specific interpretation. However, the mongo-go-driver expects an ObjectID when searching by _id.
To resolve this issue, you can use primitive.ObjectIDFromHex to convert the _id string to an ObjectID. Here's an example:
<code class="go">import ( "github.com/mongodb/mongo-go-driver/bson" "github.com/mongodb/mongo-go-driver/mongo" ) // ... objID, _ := primitive.ObjectIDFromHex("5c7452c7aeb4c97e0cdb75bf") value := collection.FindOne(ctx, bson.M{"_id": objID})</code>
This should return the desired document with the specified _id.
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