Finder

The Finder() method is used to obtain a new generic query object, namely Finder[T]. With the methods of Finder[T], we can execute relevant query operations.

Find a single document

user, err := userColl.Finder().Filter(query.Id("60e96214a21b1b0001c3d69e")).FindOne(context.Background())

• The FindOne method is used to query a single document. user is a pointer object of the specified generic type, i.e., *User.

• The Filter method allows us to specify search criteria. It accepts parameters of type any, meaning any type of argument can be passed in, provided they are valid query conditions. In the example above, query.Id("60e96214a21b1b0001c3d69e") is used to specify the search condition where _id equals 60e96214a21b1b0001c3d69e. For more on building query conditions, refer to the query package.

Find multiple documents

users, err := userColl.Finder().Filter(query.In("_id", "60e96214a21b1b0001c3d69e", "80e96214a21b1b0001c3d70e")).Find(context.Background())

• The Find method is used to query multiple documents. users is a slice of pointer objects of the specified generic type, i.e., []*User.

Count document

count, err := userColl.Finder().
		Filter(query.NewBuilder().Gt("age", 18).Lt("age", 24).Build()).
		Count(context.Background())

• The Count method is used to count the number of documents. count is of type int64.

Distinct query

// v1
//result, err := userColl.Finder().Distinct(context.Background(), "age")
//
//// you can parse the result to slices using the DistinctWithParse method
//ageSlice := make([]int, 0)
//err := userColl.Finder().DistinctWithParse(context.Background(), "age", &ageSlice)

// v2
distinctResult := userColl.Finder().Distinct(context.Background(), "age")
if distinctResult.Err() != nil {
    panic(distinctResult.Err())
}

// you can parse the result to slices using the DistinctWithParse method
ageSlice := make([]int, 0)
err := userColl.Finder().DistinctWithParse(context.Background(), "age", &ageSlice)

• The Distinct method is used to query the unique value of a specified field. mongo-driver v1 returns a result of type []any, whereas mongo-driver v2 returns a *mongo.DistinctResult.

• If you wish to parse the result into a slice, you can use the DistinctWithParse method. This method takes a pointer to a slice as a parameter for parsing the results.