用grom 自定义字段，怎么解析mysql 字符串类型的json 数组

type WarehouseCheckGoods struct {
    ID               int64     `gorm:"column:id" db:"column:id" json:"id" form:"id"`
    GoodsId          int64     `gorm:"column:goods_id" db:"column:goods_id" json:"goods_id" form:"goods_id"`
    SkuCode          string    `gorm:"column:sku_code" db:"column:sku_code" json:"sku_code" form:"sku_code"`
    Remarks          string    `gorm:"column:remarks" db:"column:remarks" json:"remarks" form:"remarks"`
    RealNumber       int64     `gorm:"column:real_number" db:"column:real_number" json:"real_number" form:"real_number"`
    BookNumber       int64     `gorm:"column:book_number" db:"column:book_number" json:"book_number" form:"book_number"`
    AdjustNumber     int64     `gorm:"column:adjust_number" db:"column:adjust_number" json:"adjust_number" form:"adjust_number"`
    WarehouseCheckId int64     `gorm:"column:warehouse_check_id" db:"column:warehouse_check_id" json:"warehouse_check_id" form:"warehouse_check_id"`
    ThreeWarehouse   AutoGenerated   `gorm:"column:three_warehouse" db:"column:three_warehouse" json:"three_warehouse" form:"three_warehouse"`
    CreatedAt        time.Time `gorm:"column:created_at" db:"column:created_at" json:"created_at" form:"created_at"`
    UpdatedAt        time.Time `gorm:"column:updated_at" db:"column:updated_at" json:"updated_at" form:"updated_at"`
}

type AutoGenerated []struct {
    WarehouseID  int    `json:"warehouse_id"`
    BookNumber   string `json:"book_number"`
    AdjustNumber string `json:"adjust_number"`
}

func (j *AutoGenerated) Scan(value interface{}) error {
    bytes, _ := value.([]uint8)
    var lins AutoGenerated
    json.Unmarshal([]byte(bytes), &lins)
//打印lins ，输出正常
    j = &lins
// 把值赋给 指针，输出是null
    return nil
}

func (j AutoGenerated) Value() (driver.Value, error) {
    return j, nil
}

其中ThreeWarehouse 这个字段为json 数组格式的字符 格式

[{"warehouse_id":1,"book_number":"0","adjust_number":"15"}]

然后我自定义的类型AutoGenerated，代码如上方，我把json绑定到结构体，打印都正常，但是赋值给指针，后接口请求不正常；哪位大神知道下，我这种怎么处理，谢谢🙏