英文:
populate array of ids from same same collection
问题
以下是您要翻译的内容：
我有一组产品，其中我将变体保存为ID数组，但这些ID数组是来自同一集合的“_ids”。现在，如果我想填充这些ID，我该怎么做？
这个集合看起来像这样。
所以我尝试了下面的填充操作，但它不起作用。
db.products.aggregate([
..........,
{ "$unwind": "$variantIdsArr" },
{ "$lookup": {
"from": "$products",
"foreignField": "_id",
"localField": "variantIdsArr",
"as": "variantIdsArr"
}},
{ "$unwind": "$variantIdsArr" },
{ "$group": {
"_id": "$_id",
"variantIdsArr": { "$push": "$variantIdsArr" }
}},
.........,
])
有人可以帮助我吗？
谢谢提前！
英文:
I have a collection of products where I've kept variants as an array of ids, but this array of ids are the _ids from the same collection. Now if I want to populate the ids how can I do that.
The collection looks like this.
So I tried to populate this as below but it does not work.
db.products.aggregate([
..........,
{"$unwind": "$variantIdsArr" },
{ "$lookup": {
"from": "$products",
"foreignField": "_id",
"localField": "variantIdsArr",
"as": "variantIdsArr"
}},
{ "$unwind": "$variantIdsArr" },
{ "$group": {
"_id": "$_id",
"variantIdsArr": { "$push": "$variantIdsArr" }
}},
.........,
])
Can anyone please help me?
Thanks in advance!
答案1
得分: 1
你的$lookup中有一个拼写错误：
{
"$lookup": {
"from": "products", // 这里应该是 `products` 而不是 `$products`
"foreignField": "_id",
"localField": "variantIdsArr",
"as": "variantIdsArr"
}
}
英文:
Your $lookup has a typo:
{
"$lookup": {
"from": "$products", // This should be `products` instead of `$products`
"foreignField": "_id",
"localField": "variantIdsArr",
"as": "variantIdsArr"
}
}
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