Aggregation Expression - $subtract

Function Build

Build $subtract with the Subtract function from the aggregation package.

// bson.D{bson.E{Key:"delta", Value:bson.D{bson.E{Key:"$subtract", Value:[]interface {}{"$end", "$start"}}}}}
result := aggregation.Subtract("delta", "$end", "$start")

Method Build (Builder)

Build $subtract with the Subtract method from aggregation.NewBuilder().

// bson.D{bson.E{Key:"delta", Value:bson.D{bson.E{Key:"$subtract", Value:[]interface {}{"$end", "$start"}}}}}
result := aggregation.NewBuilder().
    Subtract("delta", "$end", "$start").
    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.

SubtractWithoutKey

Function build:

// bson.D{bson.E{Key:"$subtract", Value:[]any{"$end", "$start"}}}
expr := aggregation.SubtractWithoutKey("$end", "$start")

Method build (Builder):

// bson.D{bson.E{Key:"$subtract", Value:[]any{"$end", "$start"}}}
expr := aggregation.NewBuilder().
    SubtractWithoutKey("$end", "$start").
    Build()