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The Database DevOps Transformation

Digital transformation is a buzzword that is often thrown about. But what isn’t discussed in depth, is how DevOps fits into the initiative and what the pitfalls are.

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Nullable vs Non-Nullable Columns and Adding Not Null Without Downtime in PostgreSQL

In this article, we are going to talk about nullable and non-nullable columns specifically related to Postgres databases. While the reasons to use nullable or non-nullable columns may seem obvious at first, there are pitfalls associated with each decision that either affect development velocity, affect application performance, or cause downtime. Let's start with definitions. Nullable […]

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What's New for the Microsoft Data Platform

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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