convert all JSON columns into new table - mysql

Question

I currently have a table structured like:
customer_id name phoneNumbers
1 Adam [{'type':'home','number':'687-5309'} , {'type':'cell','number':'123-4567'}]
2 Bill [{'type':'home','number':'987-6543'}]
With the phoneNumbers column set as a JSON column type.
For simplicity sake though I am wanting to covert all the JSON phone numbers into a new separate table.
Something like:
phone_id customer_id type number
1 1 home 687-5309
2 1 cell 123-4567
3 2 home 987-6543
It seems like it should be do-able with OPENJSON but so far I haven't had any luck in figuring out how to declare it correctly. Any help is appreciated.

Answer 1

USE recursive CTE with 1 and recurse upto json_length.
SELECT c.*, JSON_LENGTH(c.phoneNumbers) as json_length
from customers c;
then use concat to pass that element_id in Extract Query:
(json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$.type.',1))), json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$.number.',1))))
(json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$.type.',2))), json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$.number.',1))))
-
-
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(json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$.type.',json_length))), json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$.number.',json_length))))

Answer 2

You can do something like this:
SELECT id,
name,
JSON_UNQUOTE(JSON_EXTRACT(phone, CONCAT("$[", seq.i, "]", ".", "number"))) AS NUMBER,
JSON_UNQUOTE(JSON_EXTRACT(phone, CONCAT("$[", seq.i, "]", ".", "type"))) AS TYPE
FROM customer, (SELECT 0 AS I UNION ALL SELECT 1) AS seq
WHERE seq.i < json_length(phone)
The trick is (SELECT 0 as i union all SELECT 1), depends on your JSON array's length you may need to add more index. You can find out the max length by:
SELECT MAX(JSON_LENGTH(phone)) FROM customer;

Answer 3

Please change CTE defination syntax according to MySQL\Maria versions.
WITH RECURSIVE cte_recurse_json AS
(
SELECT customer_id, phone_numbers, 0 as recurse, JSON_LENGTH(c.phoneNumbers) as json_length,
json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$[',0,'].type'))) as type,
json_unquote(JSON_EXTRACT(phoneNumbers, CONCAT('$[',0,'].number'))) as number
FROM table
UNION ALL
SELECT t.customer_id, t.phone_numbers, ct.recurse + 1 as recurse, t.json_length,
json_unquote(JSON_EXTRACT(ct.phoneNumbers, CONCAT('$[',ct.recurse,'].type'))) as type,
json_unquote(JSON_EXTRACT(ct.phoneNumbers, CONCAT('$[',ct.recurse,'].number'))) as number
FROM TABLE t
INNER JOIN cte_recurse_json ct ON t.customer_id = ct.customer_id
WHERE ct.recurse < json_length
)
SELECT customer_id, type, number FROM cte_recurse_json;