SQL Server: Unexpected results with CTE when filtering on computed columns
Hey everyone, I'm running into an issue that's driving me crazy. I just started working with I need some guidance on I'm working with SQL Server 2019 and trying to use a Common Table Expression (CTE) to filter results based on a computed column, but I'm working with unexpected results... My intent is to filter records from a sales table where the computed `TotalAmount` is greater than 1000. However, the CTE seems to return rows that do not meet this condition. Here is the query I've constructed: ```sql WITH SalesCTE AS ( SELECT SalesID, ProductID, Quantity, UnitPrice, (Quantity * UnitPrice) AS TotalAmount FROM Sales ) SELECT * FROM SalesCTE WHERE TotalAmount > 1000; ``` When I run this, I see rows where `TotalAmount` is less than or equal to 1000, which confuses me. I even added a simple `SELECT` from the CTE before the final filtering just to debug: ```sql WITH SalesCTE AS ( SELECT SalesID, ProductID, Quantity, UnitPrice, (Quantity * UnitPrice) AS TotalAmount FROM Sales ) SELECT TotalAmount FROM SalesCTE; ``` The computed column seems to be correct. I checked the sales data, and it appears accurate. The relevant rows where `TotalAmount` is exactly 1000 or less should not be part of the final output. I also tried running this query without the CTE by embedding the logic directly into the `SELECT` statement: ```sql SELECT SalesID, ProductID, Quantity, UnitPrice, (Quantity * UnitPrice) AS TotalAmount FROM Sales WHERE (Quantity * UnitPrice) > 1000; ``` This version yields the expected output, so I suspect there is something specific about how the CTE is functioning that I'm not grasping. Can someone guide to figure out why I'm getting these unexpected results when using the CTE and how to correct the filtering scenario? I've been using Sql for about a year now. What's the correct way to implement this? Any pointers in the right direction?