gorm / go how to join two tables properly?

My message struct ;

type Message struct {
  Id          int    `json:"id" gorm:"primaryKey;AUTO_INCREMENT"`
  Message     string `json:"message"`
  Sender      int    `json:"sender" gorm:"foreignKey:users"`
  ChatId      int    `json:"chatid" gorm:"index"`
  CreatedAt   int64  `json:"createdat" gorm:"autoCreateTime"`
  MessageType int    `json:"messagetype"` // 0 representing text , 1 representing image
  Image       string `json:"image"`       // will be empty if the image doesn't contain image
}

My user struct;

type User struct {
  ID                 int    `gorm:"primaryKey;AUTO_INCREMENT"`
  Username           string `gorm:"not null"`
  Mail               string `gorm:"not null"`
  Password           string `gorm:"not null"`
  Updated            int64  `gorm:"autoUpdateTime:milli"`
  Created            int64  `gorm:"autoCreateTime"`
  RegisterMethod     string `gorm:"not null"`
  IsEmailValidated   bool   `gorm:"default:false"`
  IsOnboardCompleted bool   `gorm:"default:false"`
}

Here is my query ;

messages := []model.Message{}
err := r.db.Joins("inner join users on messages.sender = users.id").Where("chat_id = ?", chatid).Order("created_at desc").Limit(10).Find(&messages).Error

here is the outcome ;

 {
    "id": 1,
    "message": "csacsacsa",
    "sender": 16,
    "chatid": 0,
    "createdat": 0,
    "messagetype": 0,
    "image": ""
},

what I want to achieve is, to join user object using "sender" section like

{
        "id": 1,
        "message": "csacsacsa",
        "sender": {
          "id":16,
          "username": "bla bla bla",
          "mail": "bla bla bla" 
          ....
        },
        "chatid": 0,
        "createdat": 0,
        "messagetype": 0,
        "image": ""
},

You need to add a field to your Message struct in order to all information for the sender.

Message struct changes:

type Message struct {
  Id          int    `json:"id" gorm:"primaryKey;AUTO_INCREMENT"`
  Message     string `json:"message"`
  Sender      int    `json:"senderid" gorm:"foreignKey:users"`
  SenderObj   User   `json:"sender" gorm:"foreignKey:ID;references:Sender"`
  ChatId      int    `json:"chatid" gorm:"index"`
  CreatedAt   int64  `json:"createdat" gorm:"autoCreateTime"`
  MessageType int    `json:"messagetype"` 
  Image       string `json:"image"`       
}

With this, you can use the Preload function to load the SenderObj field.

messages := []model.Message{}
err := r.db.Preload("SenderObj").Where("chat_id = ?", chatid).Order("created_at desc").Limit(10).Find(&messages).Error