我使用查找“productdata”从“udatas”模式中获取数据。我怀疑这适用于 mongodb 4.x,但不适用于 3.6。有任何想法吗?
Udata 模式
{
"_id" : ObjectId("5f6357500153c4d59b38f1e7"),
"uId" : "112345",
"pId" : "5f63436f3d0e2bd390324847",
"sizeId" : "5f63483340421ed478f9d44e",
"general" : "4",
"length" : "5",
"width" : "3",
"height" : "5",
"comment" : "xxxxxx",
"__v" : 0
}
这是“产品”模式
{
"_id" : ObjectId("5f63436f3d0e2bd390324847"),
"brand" : "Brand A",
"name" : "product x",
"model" : "",
"color" : "Black",
"image" : "image.jpg",
"sku" : "abc12345",
"__v" : 0
}
这个我试过了,但是我得到的是空产品?
db.getCollection('udatas').aggregate([
{
$lookup: {
from: "products",
localField: "pId",
foreignField: "_id",
as: "product"
}
},
{
$project: {
"pid" :1,
"uId":1,
"comment": 1,
"product":1
}
}
])
提前致谢