db.getCollection('market').aggregate([
{
    "$match":{
        market_no: 137567
    }
},
{
    "$project": {
        market_username: 1
    }
},
{
     "$lookup": {
                        "from": "profile",
                        "localField": "market_username",
                        "foreignField": "profile_username",
                        "as": "profile"
                    }
},
{
    "$unwind": {
        "path": "$profile",
        "preserveNullAndEmptyArrays": true
    }
},
{
    "$unwind": {
        "path": "$profile.board_auth",
        "preserveNullAndEmptyArrays": true
    }
},
{
    "$project": {
        "profile.board_auth":1
    }
},
])

this is the result

/* 1 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "profile" : {
        "board_auth" : {
            "brd_no" : 110,
            "auth_bit" : 7,
            "brd_type" : "board"
        }
    }
}

/* 2 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "profile" : {
        "board_auth" : {
            "brd_type" : "club",
            "auth_type" : "owner",
            "brd_no" : 10103,
            "auth_bit" : 7
        }
    }
}

/* 3 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "profile" : {
        "board_auth" : {
            "brd_type" : "academy",
            "auth_type" : "owner",
            "brd_no" : 30002,
            "auth_bit" : 7
        }
    }
}

/* 4 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "profile" : {
        "board_auth" : {
            "brd_type" : "special",
            "auth_type" : "member",
            "brd_no" : 110,
            "auth_bit" : 0,
            "badge_no" : 4
        }
    }
}

I want to lookup depend the “profile.board_auth.brd_type”

switch profile.board_auth.brd_type {

case club: "club"

case academy: "academyInfo"

default: "badge"

}

so I tried to make mongodb Query

db.getCollection('market').aggregate([
{
    "$match":{
        market_no: 137567
    }
},
{
    "$project": {
        market_username: 1
    }
},
{
     "$lookup": {
                        "from": "profile",
                        "localField": "market_username",
                        "foreignField": "profile_username",
                        "as": "profile"
                    }
},
{
    "$unwind": {
        "path": "$profile",
        "preserveNullAndEmptyArrays": true
    }
},
{
    "$unwind": {
        "path": "$profile.board_auth",
        "preserveNullAndEmptyArrays": true
    }
},
{
    "$project": {
        "profile.board_auth":1
    }
},

{
    "$lookup": {
        "from": "club",
        "let": {
            "brd_type": "$profile.board_auth.brd_type",
            "brd_no": "$profile.board_auth.brd_no"
        },
        "pipeline": [
            {
                "$match": {
                    "$expr": {
                        "$and": [
                            { "$eq": ["$$brd_type", "club"] },
                            { "$eq": ["$$brd_no", "$club_no"]}
                        ]
                    }
                }
            }
        ],
        "as": "clubLookup"
    }
},
{
    "$lookup": {
        "from": "academyInfo",
        "let": {
            "brd_type": "$profile.board_auth.brd_type",
            "brd_no": "$profile.board_auth.brd_no"
        },
        "pipeline": [
            {
                "$match": {
                    "$expr": {
                        "$and": [
                            { "$eq": [ "$$brd_type", "academy" ] },
                            { "$eq": [ "$$brd_no", "$academy_no" ] }
                        ]
                    }
                }
            }
        ],
        "as": "academyLookup"
    }
},
{
    "$lookup": {
        "from": "badge",
        "let": {
            "brd_type": "$profile.board_auth.brd_type",
            "badge_no": "$profile.board_auth.badge_no"
        },
        "pipeline": [
            {
                "$match": {
                    "$expr": {
                        "$and": [
                            { "$eq": [ "$$brd_type", "special" ] },
                            { "$eq": [ "$$badge_no", "$badge_no" ] }
                        ]
                    }
                }
            }
        ],
        "as": "badgeLookup"
    }
},
{
    "$addFields": {
        "allLookup": {
            "$setUnion": ["$clubLookup","$academyLookup","$badgeLookup"]
        }
    }
},
{
    "$unwind": {
        "path": "$allLookup",
        "preserveNullAndEmptyArrays": true
    }
},
{
    "$addFields": {
        "allLookup": {
            "$cond": [
                {
                    "$not": "$allLookup"
                },
                "$$REMOVE",
                {
                    "$mergeObjects": [
                        [
                            {
                                "brd_type": "$profile.board_auth.brd_type",
                                "auth_type": "$profile.board_auth.auth_type",
                                "club_url_name": "$allLookup.club_url_name",
                                "club_emblem_image": "$allLookup.club_emblem_image",
                                "academy_url_name": "$allLookup.academy_url_name",
                                "academy_emblem_image": "$allLookup.academy_emblem_image",
                                "badge_name": "$allLookup.badge_name",
                                "badge_image": "$allLookup.badge_image",
                                "_id": "$allLookup._id"
                            }
                        ]
                    ]
                }
            ]
        }
    }
},

{
    "$project": {
        "allLookup":1
    }
},
])

i got final result

/* 1 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2")
}

/* 2 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "allLookup" : {
        "brd_type" : "club",
        "auth_type" : "owner",
        "club_url_name" : "10103",
        "club_emblem_image" : [ "image" ],
        "_id" : ObjectId("64e4528711945660dbcabbc7")
    }
}

/* 3 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "allLookup" : {
        "brd_type" : "academy",
        "auth_type" : "owner",
        "academy_url_name" : "30002",
        "academy_emblem_image" : [ "image" ],,
        "_id" : ObjectId("6618bf61cf9e95efa204fa61")
    }
}

/* 4 */
{
    "_id" : ObjectId("6614b6f0185079cb3d8a22f2"),
    "allLookup" : {
        "brd_type" : "special",
        "auth_type" : "member",
        "badge_name" : "name",
        "badge_image" : [ "/admin/badge/re4mo_level_3.png"],
        "_id" : ObjectId("63eb53fde7df8cb008383519")
    }
}

but my mongodb query tried lookup 3 times,

i want to lookup once depend the profile.board_auth.brd_type

so get the result faster and simple.

thank you for helping me.