Question

import "github.com/globalsign/mgo"

job := &mgo.MapReduce{
    Map:    "function() { emit(this.name, 1) }",
    Reduce: "function(key, values) { return Array.sum(values) }",
    Out:    "res",

}

_, err = c.Find(nil).MapReduce(job, nil)

如何在上述golang mgo mapreduce中添加“查询”？

参考：

https://docs.mongodb.com/manual/core/map-reduce/ https://godoc.org/github.com/globalsign/mgo#MapReduce

Answer 1

MapReduce是Find返回的Query结构的函数。因此，为了将您的MapReduce应用于查询结果，只需将查询文档添加到find函数：

c.Find(query).MapReduce(job,result)

Answer 2

设法通过MongoDb官方godriver完成此操作

"go.mongodb.org/mongo-driver/bson"
"go.mongodb.org/mongo-driver/mongo"
"go.mongodb.org/mongo-driver/mongo/options"

par := bson.D{
    {"mapreduce", "audit"},
    {"map", " function() { emit( this.name , 1 ); }"},
    {"reduce", "function(key, arr) { return Array.sum(arr); }"},
    {"out", "mr3"},
    {"query", bson.D{{"status", "SUCCESS"}}},
}

sr := db.RunCommand(nil, par)

MapReduce中的Golang GlobalSign mgo查询

2 个答案: