Andy Warren

I'm Andy Warren, currently a SQL Server trainer with End to End Training. Over the past few years I've been a developer, DBA, and IT Director. I was one of the original founders of SQLServerCentral.com and helped grow that community from zero to about 300k members before deciding to move on to other ventures.

Blog Post

Veterans Day 2013

Tonight I’ll be talking again with my children about Veteran’s Day, what it means to me, and what I hope...

2013-11-11

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Blogs

Day 2 at PASS Data Community Summit 2024

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I missed blogging yesterday as I was on stage/backstage for quite a bit of...

PASS Summit 2024 – Wednesday

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A common theme in the PASS Summits I've attended is community and that's definitely...

Taming Database Challenges: Insights from Redgate Keynote

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I am excited to cover the Microsoft Keynote on Day 2: Redgate Keynote: Simplifying...

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Forums

Deduplicating rows by choosing the row with the shortest string

By Mark Dalley

Hello T-SQL experts I have a table containing team codes and descriptions. Unfortunately, many...

query help

By Bruin

I need some help to optimize this query as it runs in many threads...

Unencrypted connections in Always on Availability Group

By Awais Afzal

Hi, In my Always On Availability environment, I am seeing two encrypt_option values as...

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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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