Bert Wagner

Blog Post

Temporary Staging Tables

Watch this week’s episode on YouTube. SQL Server Spool operators are a mixed bag. On one hand, they can negatively impact performance when writing data to disk in tempdb....

2019-05-07

256 reads

Blog Post

Temporary Staging Tables

Watch this week's video on YouTube
SQL Server Spool operators are a mixed bag. On one hand, they can negatively impact performance when writing data to disk in tempdb. On...

2019-05-07

20 reads

Blog Post

Temporary Staging Tables

Watch this week's video on YouTube
SQL Server Spool operators are a mixed bag. On one hand, they can negatively impact performance when writing data to disk in tempdb. On...

2019-05-07

14 reads

Blog Post

IN vs UNION ALL

Watch this week’s episode on YouTube. When you need to filter query results on multiple values, you probably use an IN() statement or multiple predicates separated by ORs: or...

2019-05-13 (first published: )

1,340 reads

Blog Post

IN vs UNION ALL

Watch this week's video on YouTube
When you need to filter query results on multiple values, you probably use an IN() statement or multiple predicates separated by ORs:
WHERE Col1 IN...

2019-04-30

12 reads

Blog Post

IN vs UNION ALL

Watch this week's video on YouTube
When you need to filter query results on multiple values, you probably use an IN() statement or multiple predicates separated by ORs:
WHERE Col1 IN...

2019-04-30

29 reads

Blog Post

Correlated Subqueries vs Derived Tables

Correlated subqueries provide an intuitive syntax for writing queries that return related data. However, they often perform poorly due to needing to execute once for every value they join on....

2019-05-07 (first published: )

1,744 reads

Blogs

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Announcements from the Microsoft Fabric Community Conference — Barcelona 2026

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Forums

Let's Talk Certifications

By Grant Fritchey

Comments posted to this topic are about the item Let's Talk Certifications

The Hidden Security Risks of Role Combination in SSAS Tabular

By Pablo Echeverria

Comments posted to this topic are about the item The Hidden Security Risks of...

The Empty Aggregate

By Steve Jones - SSC Editor

Comments posted to this topic are about the item The Empty Aggregate

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Question of the Day

The Empty Aggregate

I have this table in a SQL Server 2025 database:

CREATE TABLE [dbo].[CustomerOrder]
(
[OrderID] [int] NULL,
[CustomerID] [int] NULL,
[total] [money] NULL
) ON [PRIMARY]
GO
What is returned from this code? (answers are for the sum and then the count)
SELECT SUM(total) AS sum,
       COUNT(total) AS count
FROM dbo.CustomerOrder;



See possible answers