Question

我有一个带有group by语句的查询，我想将数据转换为适当的json对象

查询：

SELECT c.name, count(u.id) 
FROM users AS u 
INNER JOIN contries AS c ON u.country_id = c.id 
GROUP BY c.id

预期结果：

{canada: {count: 1565}, colombia: {count:15645612}}

Answer 1

您可以添加聚合级别并使用json_objectagg()（从MySQL 5.7开始可用）：

select json_objectagg(name, js_count) js
from (
    select c.name, json_object('count', count(u.id)) js_count
    from users as u 
    inner join contries as c on u.country_id = c.id 
    group by c.id, c.name
) t

Answer 2

SELECT JSON_OBJECT(
  'name', c.name,
  'count', count(u.id)
)
FROM users as u INNER JOIN contries AS c ON u.country_id = c.id 
GROUP BY c.id;

Answer 3

“ select return JSON”，有两种方法：

使用“ hack”-参见db-fiddle here，
或在此处使用MySQL提供的新JSON函数之一-具有讽刺意味的是，它似乎比hack本身更像是hack！只有MySQL！：（小提琴here）。

如何将mysql查询“ group by statement”结果转换为json结构？

3 个答案: