求助！！模型关联怎么做条件筛选

这是我的分类模型

这是我的查询语句

这是查询结果

{
    "code": 0,
    "msg": "请求成功",
    "count": 1,
    "data": [
        {
            "id": 1,
            "name": "一级课程",
            "level": 1,
            "parent_id": 0,
            "sort": 1,
            "status": 1,
            "describe": null,
            "created_at": "2019-08-28 23:44:42",
            "updated_at": "2019-09-23 23:06:12",
            "sal_product": [
                {
                    "id": 5,
                    "name": "A商品",
                    "level": null,
                    "parent_id": 1,
                    "sort": 1,
                    "status": 1,
                    "describe": null,
                    "created_at": "2019-09-23 22:37:53",
                    "updated_at": "2019-09-26 14:26:28",
                    "all_childs": [],
                    "articles": [
                        {
                            "id": 13,
                            "category_id": "5",
                            "teacher_id": 1,
                            "title": "日常口语",
                            "keywords": "日常口语",
                            "is_try": "1",
                            "description": "大苏打撒旦撒打算11",
                            "content": "<p>啊撒大苏打撒旦撒旦撒旦111</p>",
                            "which_lesson": 2,
                            "click": 323,
                            "vlink": "https://www.zoomus.cn/j/1534952830",
                            "host_id": "s5Oz57v-SHWaygaDTMWZ9Q",
                            "vtime": "45::00",
                            "thumb": "http://pwyk6x1kq.bkt.clouddn.com/2019-09-22_1569167243_5d87978bd7860.jpg",
                            "created_at": "2019-09-22 23:47:03",
                            "updated_at": "2019-09-26 14:06:09"
                        },
                        {
                            "id": 14,
                            "category_id": "5",
                            "teacher_id": 1,
                            "title": "疯狂英语",
                            "keywords": "疯狂英语",
                            "is_try": "0",
                            "description": "疯狂英语",
                            "content": "<p>疯狂英语</p>",
                            "which_lesson": 1,
                            "click": 204,
                            "vlink": "https://www.zoomus.cn/j/1578560990",
                            "host_id": "s5Oz57v-SHWaygaDTMWZ9Q",
                            "vtime": "45::00",
                            "thumb": "http://pwyk6x1kq.bkt.clouddn.com/2019-09-23_1569168894_5d879dfe1e5e9.jpg",
                            "created_at": "2019-09-23 00:14:56",
                            "updated_at": "2019-09-26 14:06:00"
                        }
                    ]
                }
            ]
        }
    ]
}

问题：我现在还有对课程进行筛选 查出 which_lesson = 1的课程就行 我该怎么写查询条件
我想要如下的数据

{
    "code": 0,
    "msg": "请求成功",
    "count": 1,
    "data": [
        {
            "id": 1,
            "name": "一级课程",
            "level": 1,
            "parent_id": 0,
            "sort": 1,
            "status": 1,
            "describe": null,
            "created_at": "2019-08-28 23:44:42",
            "updated_at": "2019-09-23 23:06:12",
            "sal_product": [
                {
                    "id": 5,
                    "name": "A商品",
                    "level": null,
                    "parent_id": 1,
                    "sort": 1,
                    "status": 1,
                    "describe": null,
                    "created_at": "2019-09-23 22:37:53",
                    "updated_at": "2019-09-26 14:26:28",
                    "all_childs": [],
                    "articles": [
                        {
                            "id": 14,
                            "category_id": "5",
                            "teacher_id": 1,
                            "title": "疯狂英语",
                            "keywords": "疯狂英语",
                            "is_try": "0",
                            "description": "疯狂英语",
                            "content": "<p>疯狂英语</p>",
                            "which_lesson": 1,
                            "click": 204,
                            "vlink": "https://www.zoomus.cn/j/1578560990",
                            "host_id": "s5Oz57v-SHWaygaDTMWZ9Q",
                            "vtime": "45::00",
                            "thumb": "http://pwyk6x1kq.bkt.clouddn.com/2019-09-23_1569168894_5d879dfe1e5e9.jpg",
                            "created_at": "2019-09-23 00:14:56",
                            "updated_at": "2019-09-26 14:06:00"
                        }
                    ]
                }
            ]
        }
    ]
}