SQL select from array in JSON - sql

Question

I have a table with a json field with the following json:
[
{
productId: '1',
other : [
otherId: '2'
]
},
{
productId: '3',
other : [
otherId: '4'
]
}
]
I am trying to select the productId and otherId for every array element like this:
select JSON_EXTRACT(items, $.items[].productId) from order;
But this is completely wrong since it takes only the first element in the array
Do I need to write a loop or something?

Answer 1

First of all, the data you show is not valid JSON. It has multiple mistakes that make it invalid.
Here's a demo using valid JSON:
mysql> create table orders ( items json );
mysql> insert into orders set items = '[ { "productId": "1", "other": { "otherId": "2" } }, { "productId": "3", "other" : { "otherId": "4" } } ]'
mysql> SELECT JSON_EXTRACT(items, '$[*].productId') AS productIds FROM orders;
+------------+
| productIds |
+------------+
| ["1", "3"] |
+------------+
If you want each productId on a row by itself as a scalar value instead of a JSON array, you'd have to use JSON_TABLE() in MySQL 8.0:
mysql> SELECT j.* FROM orders CROSS JOIN JSON_TABLE(items, '$[*]' COLUMNS(productId INT PATH '$.productId')) AS j;
+-----------+
| productId |
+-----------+
| 1 |
| 3 |
+-----------+
This is tested in MySQL 8.0.23.
You also tagged your question MariaDB. I don't use MariaDB, and MariaDB has its own incompatible implementation of JSON support, so I can't predict how it will work.