MySQL 5.7 - Difficulty with Grouping Results and Retaining Non-Aggregated Columns
I just started working with I'm integrating two systems and I'm stuck on something that should probably be simple. I’m currently working on a MySQL 5.7 database where I need to retrieve a list of customers along with the total amount they’ve spent, but I also want to include their last order date. The scenario arises when I try to group the results because I get errors about non-aggregated columns. Here’s the SQL query I’m using: ```sql SELECT c.id, c.name, SUM(o.amount) AS total_spent, MAX(o.order_date) AS last_order_date FROM customers c JOIN orders o ON c.id = o.customer_id GROUP BY c.id, c.name; ``` When I execute this, I receive the following behavior message: ``` behavior 1055 (42000): 'your_db.c.last_order_date' isn't in GROUP BY ``` I’ve tried modifying the query by including all non-aggregated columns in the `GROUP BY` clause, but it's not the cleanest solution. I thought MySQL 5.7's default SQL mode `ONLY_FULL_GROUP_BY` would allow me to do this, but it seems like I might not be handling it correctly. Is there a best practice to achieve this while still maintaining SQL compliance? I also want to ensure that this solution will optimize performance since the `orders` table can grow quite large. Any examples or guidance on how to structure this query correctly would be greatly appreciated. This is part of a larger application I'm building. Am I missing something obvious? This is my first time working with Sql stable.