如下，在模型中定义CreatedAtStr字段,并且加了get方法，

CreatedAtStr: {
  type: DataTypes.STRING,
  allowNull: true,
  get () {
	let time = this.getDataValue('CreatedAt') || ''
	return time ? dateStr(time) : ''
  }
}

在接口中获取的时候，该表在其他表的关联中，属性只取了Id, 但获取结果中有CreatedAtStr

where: query,
include: [
  {
	model: Comments,
	attributes: [
		'Id'
	]
  }
]

求解

获取结果

"UserId": "e2420d70-a069-11e8-bde3-057bb13f44a3",
"Comments": [
  {
	"CreatedAtStr": "",
	"Id": 4
  },
  {
	"CreatedAtStr": "",
	"Id": 5
  },
  {
	"CreatedAtStr": "",
	"Id": 6
  },
  {
	"CreatedAtStr": "",
	"Id": 7
  }
]