Handling Empty Results from LEFT JOIN with Conditional Aggregate in SQL Server 2017
I'm working through a tutorial and I've searched everywhere and can't find a clear answer. I am currently working with an scenario with a SQL query that uses a LEFT JOIN and a conditional aggregation. My goal is to retrieve data from two tables, but I am not getting the expected results when there are no matching records in the right table. Here's my query: ```sql SELECT a.Id, a.Name, COUNT(b.OrderId) AS TotalOrders FROM Customers a LEFT JOIN Orders b ON a.Id = b.CustomerId AND b.OrderDate >= '2023-01-01' GROUP BY a.Id, a.Name; ``` For customers without any orders, I expected `TotalOrders` to return `0`, but instead, I'm receiving `NULL`. I have tried using `COALESCE` to handle this situation: ```sql SELECT a.Id, a.Name, COALESCE(COUNT(b.OrderId), 0) AS TotalOrders FROM Customers a LEFT JOIN Orders b ON a.Id = b.CustomerId AND b.OrderDate >= '2023-01-01' GROUP BY a.Id, a.Name; ``` However, this doesn't resolve the scenario. The counts are still showing as `NULL` for customers without orders. I've also checked if there are any records in the `Orders` table for those customers and confirmed that there are indeed no matches. I'm running SQL Server 2017 and I'm wondering if there's a better way to ensure that I get a `0` instead of `NULL`. Any suggestions on how I can modify my query to achieve this outcome? Thank you! For context: I'm using Sql on Ubuntu. Am I missing something obvious? I've been using Sql for about a year now. What are your experiences with this? I'm working with Sql in a Docker container on Windows 11. Is there a simpler solution I'm overlooking?