m := bson.M{
    "create_time": bson.M{
      "$gte": start,
      "$lte": end,
    },
    "account": account,
    "tag": "tag",
  }
  session.DB("db").C("collect").Find(m).Count()

  //这个就可以传入Pipe
  m := []bson.M{
    {"$match": bson.M{"tag": "tag", "account": account, "create_time": bson.M{"$gte": start, "$lte": end}}},
    {"$group": bson.M{"_id": "$TagName", "count": bson.M{"$sum": 1}}},
    {"$sort": bson.M{"count": -1}},
    {"$limit": 3},
  }
  //这里就可以取到输出的数据
  var values []result
  session.DB("db").C("collect").Pipe(m).All(&values)

package main
import (
 "gopkg.in/mgo.v2"
 "log"
 "gopkg.in/mgo.v2/bson"
)
type User struct {
 Id    bson.ObjectId `bson:"_id"`
 Name   string    `bson:"name"`
 PassWord string    `bson:"pass_word"`
 Age   int      `bson:"age"`
}
func main() {
 db, err := mgo.Dial("mongodb://192.168.2.28:27017,192.168.2.28:27018,192.168.2.28:27019/")
 if err != nil {
 log.Fatalln(err)
 }
 defer db.Close()
 db.SetMode(mgo.Monotonic, true)
 c := db.DB("howie").C("person")
 //插入
 /*c.Insert(&User{
 Id:    bson.NewObjectId(),
 Name:   "JK_CHENG",
 PassWord: "123132",
 Age: 2,
 }, &User{
 Id:    bson.NewObjectId(),
 Name:   "JK_WEI",
 PassWord: "qwer",
 Age: 5,
 }, &User{
 Id:    bson.NewObjectId(),
 Name:   "JK_HE",
 PassWord: "6666",
 Age: 7,
 })*/
 var users []User
 c.Find(nil).All(&users) //查询全部数据
 log.Println(users)
 c.FindId(users[0].Id).All(&users) //通过ID查询
 log.Println(users)
 c.Find(bson.M{"name": "JK_WEI"}).All(&users) //单条件查询(=)
 log.Println(users)
 c.Find(bson.M{"name": bson.M{"$ne": "JK_WEI"}}).All(&users) //单条件查询(!=)
 log.Println(users)
 c.Find(bson.M{"age": bson.M{"$gt": 5}}).All(&users) //单条件查询(>)
 log.Println(users)
 c.Find(bson.M{"age": bson.M{"$gte": 5}}).All(&users) //单条件查询(>=)
 log.Println(users)
 c.Find(bson.M{"age": bson.M{"$lt": 5}}).All(&users) //单条件查询(<)
 log.Println(users)
 c.Find(bson.M{"age": bson.M{"$lte": 5}}).All(&users) //单条件查询(<=)
 log.Println(users)
 /*c.Find(bson.M{"name": bson.M{"$in": []string{"JK_WEI", "JK_HE"}}}).All(&users) //单条件查询(in)
 log.Println(users)
 c.Find(bson.M{"$or": []bson.M{bson.M{"name": "JK_WEI"}, bson.M{"age": 7}}}).All(&users) //多条件查询(or)
 log.Println(users)
 c.Update(bson.M{"_id": users[0].Id}, bson.M{"$set": bson.M{"name": "JK_HOWIE", "age": 61}}) //修改字段的值($set)
 c.FindId(users[0].Id).All(&users)
 log.Println(users)
 c.Find(bson.M{"name": "JK_CHENG", "age": 66}).All(&users) //多条件查询(and)
 log.Println(users)
 c.Update(bson.M{"_id": users[0].Id}, bson.M{"$inc": bson.M{"age": -6,}}) //字段增加值($inc)
 c.FindId(users[0].Id).All(&users)
 log.Println(users)*/
 //c.Update(bson.M{"_id": users[0].Id}, bson.M{"$push": bson.M{"interests": "PHP"}}) //从数组中增加一个元素($push)
 c.Update(bson.M{"_id": users[0].Id}, bson.M{"$pull": bson.M{"interests": "PHP"}}) //从数组中删除一个元素($pull)
 c.FindId(users[0].Id).All(&users)
 log.Println(users)
 c.Remove(bson.M{"name": "JK_CHENG"})//删除
}