从 json 字段 mysql 中的键值对列表中提取一个键

Question

我有以下格式的数据：

"article_body" : [
        {
            "article_desc" : "THURSDAY, Sept. 1, 2016 (HealthDay News) -- Dapagliflozin improves insulin sensitivity and increases lipid oxidation and plasma ketone concentration in patients with type 2 diabetes mellitus (T2DM), according to a study published online Aug. 25 in Diabetes Care. \n\n Giuseppe Daniele",
            "links" : [{
                    "link_name" : "Full Text (subscription or payment may be required)"}
            ]}
    ],

我想提取密钥

article_desc

从article_body.

我在 Mysql 中的代码片段：

SELECT 

    JSON_EXTRACT(full_article_json, '$.article_body."article_desc"') AS description,
FROM
    wc_article_full_data;

我得到空数据，如何解析这些数据？

Answer 1

你的key = 'article_body'是一个数组JSON，所以你需要使用索引来获取数据。

你可以试试这个。

架构（MySQL v5.7）

CREATE TABLE wc_article_full_data(

   full_article_json JSON
);

insert into wc_article_full_data values (
'{"article_body" : [
    {
        "article_desc" : "THURSDAY, Sept. 1, 2016 (HealthDay News) -- Dapagliflozin improves insulin sensitivity and increases lipid oxidation and plasma ketone concentration in patients with type 2 diabetes mellitus (T2DM), according to a study published online Aug. 25 in Diabetes Care.  Giuseppe Daniele",
        "links" : [{
                "link_name" : "Full Text (subscription or payment may be required)"}
        ]}
]}');

查询#1

SELECT JSON_EXTRACT(full_article_json,'$.article_body[0].article_desc') AS descriptio
FROM wc_article_full_data;

| descriptio                                                                                                                                                                                                                                                                                 |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| "THURSDAY, Sept. 1, 2016 (HealthDay News) -- Dapagliflozin improves insulin sensitivity and increases lipid oxidation and plasma ketone concentration in patients with type 2 diabetes mellitus (T2DM), according to a study published online Aug. 25 in Diabetes Care.  Giuseppe Daniele" |

在 DB Fiddle 上查看

article_desc如果你想从数组中获取所有值article_body。您可以尝试在索引中使用*。

SELECT JSON_EXTRACT(full_article_json,'$.article_body[*].article_desc') AS descriptio
FROM wc_article_full_data