i have the same case as in this question: $lookup on ObjectId's in an array (i can't comment on the question since i don't have enough reputation... sorry for the duplication..) - but the query doesn't work for me and i get an empty array in the end of it.
i want to get a list of companies with a field of its positions, but the positions field is always empty on the following code. (i get the company fields, and with the $unwind - even the company fields are not returned).
what am i doing wrong?
mongoose version: 5.7.14 mongodb version: 4.2.3
i also tried a lot of combinations of aggregation and populate and none of them succeeded.
const schema = new Schema(
{
email: {
type: String,
required: true,
unique: true
},
name: {
type: String,
required: true,
unique: true
},
positionsIds: [{
type: Schema.Types.ObjectId,
ref: 'Position',
require: false
}
);
module.exports = mongoose.model('Company', schema);
-----------------------------
const schema = new Schema(
{
title: {
type: String,
required: true
},
requirements: [{
years: { type: Number, required: false },
skill: { type: String, required: false },
}],
companyId: {
type: Schema.Types.ObjectId,
ref: 'Company',
required: true
},
}
);
module.exports = mongoose.model('Position', schema );
---------------------------
let companies = await Company.aggregate([
{
$lookup:
{
from: 'Position',
localField: '_id',
foreignField: 'companyId',
as: 'positions'
}
},
// {
// $unwind: '$positions' // - mess the query even more and return an empty array
// },
]);