PostgreSQL: Unexpected results with CTEs when filtering on aggregated columns
I've spent hours debugging this and I'm trying to configure I just started working with Hey everyone, I'm running into an issue that's driving me crazy. I tried several approaches but none seem to work. I'm experiencing strange behavior when using Common Table Expressions (CTEs) in PostgreSQL 15. After aggregating data in a CTE, I want to filter on the aggregated results, but it seems like the filter is not applying correctly, leading to unexpected rows in my final result. Here's a simplified version of what I'm trying to achieve: ```sql WITH SalesSummary AS ( SELECT product_id, SUM(sales_amount) AS total_sales FROM sales GROUP BY product_id ) SELECT * FROM SalesSummary WHERE total_sales > 1000; ``` In this example, I expect only the products with total sales over 1000 to be returned. However, I noticed that some products with total sales below 1000 are still appearing in the results. To troubleshoot, I ran the following query separately to verify the aggregated results: ```sql SELECT product_id, SUM(sales_amount) AS total_sales FROM sales GROUP BY product_id; ``` The output from the aggregation looks correct, and when I manually filter the results, I see the expected behavior. I also tried replacing the CTE with a subquery and got the same scenario, which makes me wonder if it's related to how I handle the data or possibly an scenario with the PostgreSQL version. Has anyone else encountered this question, or does anyone have insights on why the filtering might be failing like this? Any suggestions for how to properly filter on aggregated columns in a CTE would be greatly appreciated. For context: I'm using Sql on Linux. Thanks in advance! What are your experiences with this? What's the correct way to implement this? This is my first time working with Sql 3.9. Hoping someone can shed some light on this. Any examples would be super helpful.