数据库中text数据 text：

• "_id": "XXXXXX"
• "_openid": "XXXXX"
• "children": [
• {"desc":"qwr","originPrice":"req","price":"wer","tag":"w...}
• {"desc":"wq","originPrice":"wqr","price":"ewqr","tag":"e...}
• {"desc":"wq","originPrice":"wqr","price":"ewqr","tag":"e...}
• {"desc":"wq","originPrice":"wqr","price":"ewqr","tag":"e...}
• ]
• "shopName":"ssd"

使用 update删除children中的一条数据，显示null

const db= wx.cloud.database()

db.collection("text").doc(_id).update({

data:{

[ 'children.' + index_item] : db.command.remove()

}

})

怎么把null去掉呢