Golang SQL扫描界面-扫描到界面字段类型？

So I have a struct, something like this:

type Torrent struct {
    ID       uint64   `db:"id"`
    Metadata Metadata `db:"metadata"`
    Category uint8    `db:"category"`
    // Many other fields
}

Metadata is an interface type, in SQL is a LONGTEXT (MariaDB's JSON type). So I have something like this:

type Metadata interface {
  // multiple funcs
}

type Category1 struct {} // implementing Metadata interface
type Category2 struct {} // implementing Metadata interface

What I would like to do is somehow scan the data from SQL into the exact struct based on the Category field. How could I achieve this?