加载具有关联的模型

Question

我想加载帖子，并且是作者id和电子邮件，而不加载任何其他内容。

它不需要急于加载，我只需要得到所有的帖子，只包括作者id和用户名

我当前的查询

posts := []interfaces.Post{}
db.Model("User").Find(&posts)

type Post struct{
gorm.Model
Title string
Body string
UserID uint
User User
}
type User struct{
gorm.Model
Username string
Email string
Password string
}

当前响应

{
"ID": 1,
"CreatedAt": "2021-01-09T19:11:42.063274-05:00",
"UpdatedAt": "2021-01-09T19:11:42.063274-05:00",
"DeletedAt": null,
"Title": "What does the fox say",
"Body": "whawhhwjg",
"UserID": 1,
"User": {
"ID": 1,
"CreatedAt": "2021-01-09T19:01:28.70267-05:00",
"UpdatedAt": "2021-01-09T19:01:28.70267-05:00",
"DeletedAt": null,
"Username": "12345",
"Email": "[e-mail]",
"Password": "$2a$04$T1841Dc52MwjSJ2PaPnTwuFASai6zkGw8WFcuQbO1fi9Nug7R3Iqq"
}
},

响应我正在寻找

{
"ID": 1,
"CreatedAt": "2021-01-09T19:11:42.063274-05:00",
"UpdatedAt": "2021-01-09T19:11:42.063274-05:00",
"DeletedAt": null,
"Title": "What does the fox say",
"Body": "whawhhwjg",
"UserID": 1,
"User": {
"ID": 1,
"Username": "12345",
}
},

Answer 1

您可以使用Select方法来选择特定字段。

dm.Model("User").Select("ID", "Email", "Username").Find(&posts)

或者，您可以像这样使用Preload方法。

db.Preload("User", func (db *gorm.DB) *gorm.DB {
return db.Select("ID", "Email", "Username")
}).
Find(&posts)

Answer 2

• 您也可以这样做

db.Preload("User").Select("ID", "Username").Find(&posts)