根据数组中的值进行查找

Question

我在mongoose中有以下模式:

userSchema = new mongoose.Schema({
name: {
type: String, 
required: true
},
team: {
type: Schema.Types.ObjectId, ref: 'Team',required:true
}
})
teamSchema = new mongoose.Schema({
name: {
type: String, 
required: true
}
coaches: []
})

我想加入这些集合，如果用户id在coaches字段，这是一个字符串数组，在团队方案中。

在连接之后，我需要过滤以获得在其coaches属性中具有特定id的用户。

因此，此处不适合使用populate。我试图使用查找，但找不到正确的方法来做到这一点。有什么想法吗?

Answer 1

• $match在coaches数组中的用户id
• $addFields编辑coaches数组
• $map循环coaches数组
• $toObjectId将字符串类型coachesid转换为objectId类型
• $lookupwith users collection

let result await Team.aggregate([
{ $match: { coaches: "5a934e000102030405000001" } },
{
$addFields: {
coaches: {
$map: {
input: "$coaches",
in: { $toObjectId: "$$this" }
}
}
}
},
{
$lookup: {
from: "users", // update to correct users collection name
localField: "coaches",
foreignField: "_id",
as: "coaches"
}
}
])

游乐场

Answer 2

你正在使用Mongoosejs，我认为你不需要做很多，只需要在它们之间建立适当的关系，就像

teamSchema = new mongoose.Schema({
name: {
type: String, 
required: true
}
coaches: [{ type: Schema.Types.ObjectId, ref: 'User' }] // where User is model name 
})

和如何使用

Team.findOne({ name: 'team1' }).populate('coaches').exec();
// or with find
Team.find().populate('coaches').exec();

裁判:https://mongoosejs.com/docs/populate.html

基于注释更新

如果你需要传递查询和投影，那么

Team.find().populate({
path: 'coaches',
match: { name: 'User1' },
select: 'name -_id' // only user name, remove _id
}).exec();

裁判:https://mongoosejs.com/docs/populate.html query-conditions