MySQL 8.0: Unexpected Results with JSON_ARRAYAGG when Grouping by Multiple Columns
I keep running into I'm deploying to production and I've spent hours debugging this and I'm working with an unexpected scenario when trying to use `JSON_ARRAYAGG` in MySQL 8.0 while grouping by multiple columns. I want to aggregate JSON objects based on two columns, but the output doesn't seem to match my expectations. Here's my SQL query: ```sql SELECT department_id, employee_id, JSON_ARRAYAGG(employee_name) AS employees FROM employees GROUP BY department_id, employee_id; ``` The `employees` field should return the names of employees grouped by `department_id`, but instead, I get multiple JSON arrays for each employee within the same department. The output looks like this: ``` department_id | employee_id | employees ---------------|-------------|---------------------------------------------------- 1 | 101 | ["Alice"] 1 | 102 | ["Bob"] 2 | 201 | ["Charlie"] ``` What I really want is a single array of all employee names for each department. I tried modifying my query to group only by `department_id`: ```sql SELECT department_id, JSON_ARRAYAGG(employee_name) AS employees FROM employees GROUP BY department_id; ``` This approach gives me the desired results, but I need to include `employee_id` for some additional logic later. I've also checked the documentation but couldn't find any relevant examples for this specific case. Am I missing something in how `JSON_ARRAYAGG` interacts with grouping in MySQL? Any best practices or tips that can guide to achieve the intended result would be greatly appreciated. Thanks! I'm developing on CentOS with Sql. Is there a simpler solution I'm overlooking? My team is using Sql for this REST API. Any ideas what could be causing this? I'm using Sql 3.11 in this project. Any feedback is welcome!