MySQL 8.0: Unexpected results when using GROUP BY with non-aggregated columns
This might be a silly question, but I'm sure I'm missing something obvious here, but I'm working with an scenario with MySQL 8.0 where my query returns unexpected results when I use GROUP BY alongside non-aggregated columns. I have a table named `sales` with the following schema: ```sql CREATE TABLE sales ( id INT PRIMARY KEY, product_name VARCHAR(100), quantity INT, sale_date DATE ); ``` When I run the following query to aggregate the total quantity sold per product and also include the latest sale date for each product, I expect to get one row per product with the correct total quantity and the latest sale date: ```sql SELECT product_name, SUM(quantity) AS total_quantity, MAX(sale_date) AS last_sale_date FROM sales GROUP BY product_name; ``` However, sometimes I get results that seem inconsistent. For instance, for `product_name` 'Widget A', I expected the latest sale date to be `2023-10-01`, but it shows `2023-09-25` instead. I verified the data in the `sales` table and confirmed that `2023-10-01` is indeed the latest date. I've also tried using the `ANY_VALUE()` function for the `sale_date`, but it didn't solve the question: ```sql SELECT product_name, SUM(quantity) AS total_quantity, ANY_VALUE(sale_date) AS random_sale_date FROM sales GROUP BY product_name; ``` I suspect it might be related to how MySQL handles non-aggregated fields in GROUP BY queries, especially with `MAX()`. Any insights on why this is happening or how I can correctly retrieve the latest sale date while aggregating the quantities? This is part of a larger CLI tool I'm building. Any ideas what could be causing this?