在mysql 5.7中从json数组中提取密钥

Question

I have a table with json column. Below is the example:table employee

id emp_json
1 {"details" : [{"10":"909"},{"11":"910"}]}
2 {"details" : [{"20":"809"},{"21":"810"}]}

Now i want to extract the ids from the json array

I have tried with below query.

SELECT JSON_KEYS(JSON_EXTRACT(u.emp_json, '$.details'), '$[0]') FROM employee u ;

but this is giving me only one key in the result which is from the first object of array. As per my understanding this is beacuase of $[0]

Expected is

id json_key
1  10
1  11
2  20
2  21

Thanks in advance

Answer 1

This will give you comma separated, you are selecting only the index 0 , you should select 1

SELECT
id,
CONCAT(
   JSON_KEYS(JSON_EXTRACT(u.emp_json, '$.details'), '$[0]'),
   ",",
   JSON_KEYS(JSON_EXTRACT(u.emp_json, '$.details'), '$[1]')
) As json_key
FROM employee u ;

Output :-

| id  | json_key      |
| --- | ------------- |
| 1   | ["10"],["11"] |
| 2   | ["20"],["21"] |