如何使用GORM获取相关数据？

我想从其他表中获取相关数据

我有以下模型结构

type Community struct {
    ID       string            `json:"id" gorm:"primaryKey"`
    Name     string            `json:"name"`
    Category CommunityCategory `json:"category" gorm:"foreignKey:ID"`
}
type CommunityCategory struct {
    ID   uint32 `json:"id" gorm:"primaryKey"`
    Name string `json:"name"`
}

我获取数据的代码是这样的

community := Community{ID: 1}
database.Debug().Joins("CommunityCategory").First(&community)

SELECT "communities"."id","communities"."name","communities"."introduction","communities"."address","communities"."postal_code","communities"."country","communities"."address1","communities"."address2","communities"."prefecture","communities"."city","communities"."lat","communities"."lng","communities"."phone","communities"."email","communities"."external_link_1","communities"."external_link_2","communities"."image_url","communities"."access","communities"."description","communities"."contact_name","communities"."contact_phone","communities"."contact_email","communities"."is_enabled","communities"."created_at","communities"."updated_at" FROM "communities" CommunityCategory WHERE "communities"."id" = '25b1eadf-1004-40b7-b9a2-325a83bcb938' ORDER BY "communities"."id" LIMIT 1

有了这些，我得到了以下错误

错误：对表\“communities\（SQLSTATE 42P01）

查看GORM的调试日志，查询如下

community := Community{ID: 1}
database.Debug().Joins("CommunityCategory").First(&community)

SELECT "communities"."id","communities"."name","communities"."introduction","communities"."address","communities"."postal_code","communities"."country","communities"."address1","communities"."address2","communities"."prefecture","communities"."city","communities"."lat","communities"."lng","communities"."phone","communities"."email","communities"."external_link_1","communities"."external_link_2","communities"."image_url","communities"."access","communities"."description","communities"."contact_name","communities"."contact_phone","communities"."contact_email","communities"."is_enabled","communities"."created_at","communities"."updated_at" FROM "communities" CommunityCategory WHERE "communities"."id" = '25b1eadf-1004-40b7-b9a2-325a83bcb938' ORDER BY "communities"."id" LIMIT 1

---

我做错了吗？Lol通过如下定义my struct来修复此问题。我在

社区

结构中添加了一个新字段

CategoryID

，并将外键更改为这个新字段

type Community struct {
    ID         string            `json:"id" gorm:"primaryKey"`
    Name       string            `json:"name"`
    CategoryID uint32
    Category   CommunityCategory `json:"category" gorm:"foreignKey:CategoryID"`
}

type CommunityCategory struct {
    ID   uint32 `json:"id" gorm:"primaryKey"`
    Name string `json:"name"`
}

然后在查询时，您可以执行如下连接：

community := Community{ID: 1}
database.Model(&Community{}).Joins("Category").First(&community)

---

我想我现在离让它工作又近了一步。我刚刚将

连接

的参数改为

类别

，而不是

社区类别

。但是现在执行的查询是这样的：

SELECT“communities”；“id”；“Category”；“id”作为“Category”；“Category”；“name”作为“Category”；“communities”的“Category”；“communities”的“Category”；“id”；“id”；“id”=“25b1eadf-1004-40b7-b9a2-325a83bcb938”按“communities”；“id”排序限制1

但现在表的连接错误。它应该是communities.category\u id=category.id您可以尝试

database.Debug（）.Preload（“category”）。首先（&community）

，但您必须测试它是否正确使用外键并找到数据。