i have two models relationship with mongoose. my first model looks like this:

const gradeSchema = new Schema(
    {
        grade_name: {
            type: String,
            required: true,
            uppercase: true
        },
        major: {
            type: Schema.Types.ObjectId,
            ref: "Major"
        },
        active: {
            type: Boolean,
            default: true
        }
    },
    {
        timestamps: true
    }
)

and my second models like this:

const majorSchema = new Schema(
    {
        major_name: {
            type: String,
            required: true,
        },
        major_type: {
            type: String,
            required: true,
            minLength: 2,
            unique: true,
            uppercase: true
        },
        active: {
            type: Boolean, 
            default: true
        }
    },
    {
        timestamps: true
    }
)

i want to get all grades by major but i want majors to be filtered by active.

i try using populate.match but i got the majors response null:

const grade = await Grade.find()
            .populate({
                path: "major",
                match: {
                    active: true
                },
                select: "-_id major_name major_type"
            })
            .where("active")
            .equals(true)
            .exec()

CodePudding user response：

You can make use of aggregation concept in mongo.

const data = await Grade.aggregate([
    {
        $match : {}
    },
    {
        $lookup : {
            "from" : "majors",
            "pipeline" : [
                {
                    $match : {
                        "active" : true
                    }
                }
            ],
            "as" : "majorInfo"
        }
    }
]).exec()