Aggregation Expression - $last

Function Build

Build $last with the Last function from the aggregation package.

// bson.D{bson.E{Key:"lastName", Value:bson.D{bson.E{Key:"$last", Value:"$name"}}}}
result := aggregation.Last("lastName", "$name")

Method Build (Builder)

Build $last with the Last method from aggregation.NewBuilder().

// bson.D{bson.E{Key:"lastName", Value:bson.D{bson.E{Key:"$last", Value:"$name"}}}}
result := aggregation.NewBuilder().
    Last("lastName", "$name").
    Build()

Build Without Key

When an expression needs to be passed as an argument to another expression, use a WithoutKey variant to build an expression fragment without an output field name.

LastWithoutKey

Function build:

// bson.D{bson.E{Key:"$last", Value:"$name"}}
expr := aggregation.LastWithoutKey("$name")

Method build (Builder):

// bson.D{bson.E{Key:"$last", Value:"$name"}}
expr := aggregation.NewBuilder().
    LastWithoutKey("$name").
    Build()