[gorm]关联查询问题

我有type如下： ```go type Citizen struct { gorm.Model Name string `gorm:"unique"` IDc IDCard `gorm:"foreignKey:CitizenID"` } type IDCard struct { gorm.Model Color string CitizenID int } ``` 创建若干数据： ```go c1 := &Citizen{Name: "Citizen_1", IDc: IDCard{Color: "yellow"}} c2 := &Citizen{Name: "Citizen_2", IDc: IDCard{Color: "yellow"}} c3 := &Citizen{Name: "Citizen_3", IDc: IDCard{Color: "red"}} c4 := &Citizen{Name: "Citizen_4", IDc: IDCard{Color: "ready"}} ``` 现在我想要查询一个时间段中建立的Citizen数据, 并且他们的IDCard颜色中带有"re"： ```go var result []Citizen ss := _db //筛选时间 ss = ss.Where("created_at BETWEEN ? AND ?", time.Unix(0, 0), time.Unix(time.Now().Unix()+100, 0)) //筛选 IDCard 颜色： 查询所有IDCard.color中带有 “re” 的 Citizen ss = ss.Joins("IDc").Where("color LIKE ?", "%"+"re"+"%") //查询结果 ss = ss.Preload("IDc").Find(&result) ``` 但是报了错 :`ambiguous column name: created_at`, 这个是因为两个表中都有这个字段，产生的。我应该如何将这个条件应用到Citizen表中？ debug sql: ``` ```