MySQL 8.0: Issues with CASE statement in SELECT query returning unexpected NULL values
I've been working on this all day and I'm working on a project and hit a roadblock. After trying multiple solutions online, I still can't figure this out. I'm experiencing an issue with a `CASE` statement in a `SELECT` query that is returning unexpected `NULL` values. I am using MySQL 8.0 and trying to categorize data based on a couple of conditions. For example, I have a table named `orders` with columns `amount` and `status`, and I want to categorize the orders based on their `amount` like this: ```sql SELECT id, amount, CASE WHEN amount < 100 THEN 'Low' WHEN amount BETWEEN 100 AND 500 THEN 'Medium' WHEN amount > 500 THEN 'High' ELSE NULL END AS category FROM orders; ``` However, I am getting `NULL` for some rows where I expect a classification. I checked the `amount` values, and they seem to be correct. Here’s a sample of what the `orders` table looks like: | id | amount | |----|--------| | 1 | 50 | | 2 | 150 | | 3 | 600 | | 4 | NULL | | 5 | 450 | I’ve tried adding an additional check to see if `amount` is `NULL` like this: ```sql CASE WHEN amount IS NULL THEN 'Unknown' WHEN amount < 100 THEN 'Low' ... END AS category ``` But this doesn’t seem to resolve my issue. The `NULL` values in the `amount` column are still resulting in a `NULL` output for the `category`. I also verified that there are no leading/trailing spaces or other formatting issues in the `amount` field. Is there a specific reason why the `CASE` statement is not classifying the `amount` correctly when it contains `NULL`, and how can I handle this more effectively? I'm working on a application that needs to handle this. Is there a better approach? Any help would be greatly appreciated! I've been using Sql for about a year now. Any advice would be much appreciated.