JQL 简单的一对一关联查询怎么写？不是一对多，官网一对多属于嵌套格式。

schema1:

{  
    "bsonType": "object",  
    "required": [],  
    "permission": {  
        "read": true,  
        "create": true,  
        "update": true,  
        "delete": true  
    },  
    "properties": {  
        "_id": {  
            "description": "ID，系统自动生成"  
        },  
        "username": {  
            "description": "用户名称"  
        },  
        "nickname": {  
            "description": "用户昵称"  
        },  
        "openid": {  
            "bsonType": "string",  
            "foreignKey": "byepoor-records.openid",  
            "description": "用户小程序的唯一标识"  
        }  
    }  
}

schema2:

{  
    "bsonType": "object",  
    "required": [],  
    "permission": {  
        "read": true,  
        "create": true,  
        "update": true,  
        "delete": true  
    },  
    "properties": {  
        "_id": {  
            "description": "ID，系统自动生成"  
        },  
        "openid": {  
            "description": "用户小程序的唯一标识"  
        },  
        "maxScore": {  
            "description": "历史最高分"  
        }  
    }  
}

期望结果：

{  
        "_id": "67eb4b58f2949ccbd1a49de2",  
        "nickname": "摆谱",  
        "maxScore": 0,  
        "openid": "wx6239430d15e308ab"  
}

实际结果：

{  
    "_id": "67eb4b58f2949ccbd1a49de2",  
    "nickname": "摆谱",  
    "openid": [{  
        "_id": "67eb4d22862066ed973156f3",  
        "maxScore": 0,  
        "openid": "wx6239430d15e308ab"  
    }]  
}