我该如何在golang gorm与自己建立多对多关系？

I have a psql Database, and I am using the gorm library as well as the pq driver, as you see there is a many to many relationship for related products, however this throws out the error pq: column "product_id" specified more than once is there a way to set an alias or am I going about this the wrong way?

type Product struct {
    Id          int64      `json:"_id"`
    Price       float32    `json:"price"`
    Name        string     `sql:"size:255" json:"name"`
    Description string     `json:"description"`
    Material    string     `json:"material"`
    Color       string     `json:"color"`
    ColorId     int64      `json:"colorId"`
    Categories  []Category `gorm:"many2many:product_categories;" json:"categories"`
    Images      []Image    `json:"images"`
    Tags        []Tag      `gorm:"many2many:product_tags;" json:"tags"`
    Main        bool       `json:"main"`
    Available   bool       `json:"available"`
    Slug        string     `json:"slug"`
    CreatedAt   time.Time  `json:"createdAt"`
    Related     []Product  `gorm:"many2many:related_products;" json:"related"`
}

I've found the solution of self-referencing many2many relationship. :D

type User struct {
    Id int64
    Related     []Product  `gorm:"foreignkey:product_id;associationforeignkey:related_product_id;many2many:related_products;" json:"related"`        
}

Kinda old post but fortunately gorm have added lately this feature (reference: here).

In your case should be like this:

type Product struct {
  Id          int64      `json:"_id"`
  .
  .
  .
  Related     []Product `gorm:"many2many:related_products;association_jointable_foreignkey:related_id"`
}