SQLServerCentral Editorial

A New Year, New Efforts

Happy New Year! You're going to be seeing a lot of summaries for 2022 and predictions for 2023 around this time of year. I'm not writing one of those. You'll also see people calling for new years resolutions and the like. I'm not going for that either. Nope, let's keep it simple. It is a […]

SQLServerCentral Editorial

Looking Back at 2022

This is the last workday of 2022. Next week starts a new year, and as I've often done, I wanted to look back at the year. This time I decided to look back month by month, at some of the headlines and memorable data-related topics. I'm tackling things month-by-month. In January there was a set […]

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By Steve Jones - SSC Editor

Comments posted to this topic are about the item What's New for the Microsoft...

Using Outer Joins

By Steve Jones - SSC Editor

Comments posted to this topic are about the item Using Outer Joins

Closest to ProcDate

By boehnc

Not sure I have this 2nd left join correct. I need to grab the...

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Question of the Day

Using Outer Joins

I have this data in a SQL Server 2019 database:

Customer table
CustomerID CustomerName
1          Steve
2          Andy
3          Brian
4          Allen
5          Devin
6          Sally

OrderHeader table
OrderID CustomerID OrderDate
1       1          2024-02-01
2       1          2024-03-01
3       3          2024-04-01
4       4          2024-05-01
6       4          2024-05-01
7       3          2024-06-07
8       2          2024-04-07
I want a list of all customers and their order counts for a period of time, including zero orders. If I run this query, how many rows are returned?
SELECT 
  c.CustomerName, COUNT(oh.OrderID)
 FROM dbo.Customer AS c
LEFT JOIN dbo.OrderHeader AS oh ON oh.CustomerID = c.CustomerID
WHERE oh.Orderdate > '2024/04/01'
GROUP BY c.CustomerName

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