MySQL 8.0 - implementing Incrementing a Column Based on Another Column's Value
I've been researching this but I've searched everywhere and can't find a clear answer. I'm having trouble with I'm working with a question in MySQL 8.0 where I need to increment a `quantity` column based on the `status` of a related `order` column. The requirement is to increase `quantity` by 1 for each order that has the `status` set to 'completed'. I initially tried to implement this with a simple update query, but I'm working with unexpected results. My current query looks like this: ```sql UPDATE products SET quantity = quantity + ( SELECT COUNT(*) FROM orders WHERE orders.product_id = products.id AND orders.status = 'completed' ) WHERE id IN (SELECT product_id FROM orders WHERE status = 'completed'); ``` However, the `quantity` is not updating correctly, and sometimes it returns null values when there are no completed orders. I also received this behavior when running the query: ``` behavior 1242 (21000): Subquery returns more than 1 row ``` I tried to modify the query by ensuring the subquery returns a single value, but it doesn't seem to solve the scenario. Instead, I'm considering using a stored procedure to handle this logic more effectively. Is there a better way to achieve this, or should I stick with the stored procedure? What are the best practices for handling such updates in MySQL? Any insights would be appreciated! I'm using Sql 3.10 in this project. Any help would be greatly appreciated! This is my first time working with Sql stable. What are your experiences with this?