MYSQL查询返回JSON格式的字符串（多层嵌套）

简单的JSON格式请参看这篇博客：（https://blog.csdn.net/qq_39706570/article/details/104021291），本篇博客介绍复杂的嵌套方法。

表数据：

查询展示效果：

{
    "department_no": [
        {
            "001": [
                {"department_name": "诊疗部","doctor_name": "黄裳","doctor_no": "100011"},
                {"department_name": "诊疗部","doctor_name": "花满楼","doctor_no": "100012"}
            ]
        },
        {
            "002": [
                {"department_name": "护理部","doctor_name": "风清扬","doctor_no": "100013"},
                {"department_name": "护理部","doctor_name": "杨清风","doctor_no": "100014"}
            ]
        }
    ]
}

查询方式：

SELECT CONCAT("{\"department_no\":[",GROUP_CONCAT(a.msg),"]}") FROM 
(
SELECT 
CONCAT("{\"",department_no,"\":"
"[",
GROUP_CONCAT(
"{"
"\"department_name\":\"",department_name,"\",",
"\"doctor_name\":\"",doctor_name,"\",",
"\"doctor_no\":\"",doctor_no,"\"","}"
),"]}"
) msg
FROM basic_hospital_information GROUP BY department_no
)a

注意：以上SQL查询方法是使用了

GROUP_CONCAT()

该函数有长度限制，一般默认长度为1024，可以使用这篇博客（https://blog.csdn.net/qq_39706570/article/details/103999965）轻松修改长度范围。

备注：小编写这篇博客不易，希望大家能给我点个赞，谢谢。