Predicate Execution Order on Mixed Data Type Columns

• by Bert Wagner

• Bert Wagner

Watch this week’s episode on YouTube. SQL Server’s cost-based query optimizer does a pretty good job of figuring out what order to filter your data to get fast query...

2019-06-04 (first published: 2019-05-21)

417 reads

Animating a Magic 8 Ball in SQL Server Management Studio

• by Bert Wagner

• Bert Wagner

This post is a response to this month’s T-SQL Tuesday #114 prompt by Matthew McGiffen.  T-SQL Tuesday is a way for the SQL Server community to share ideas about different database...

2019-05-24 (first published: 2019-05-14)

733 reads

IN vs UNION ALL

• by Bert Wagner

• Bert Wagner

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: 2019-04-30)

1,179 reads

Correlated Subqueries vs Derived Tables

• by Bert Wagner

• Bert Wagner

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: 2019-04-23)

1,327 reads

Temporary Staging Tables

• by Bert Wagner

• Bert Wagner

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

142 reads

Window Functions vs GROUP BYs

• by Bert Wagner

• Bert Wagner

There are many options available for improving the performance of a query: indexes, statistics, configuration settings, etc… However, not all environments allow you to use those features (eg. vendor...

2019-04-25 (first published: 2019-04-16)

1,150 reads

Data Type Precedence and Implicit Conversions

• by Bert Wagner

• Bert Wagner

SQL Server needs to make sure data types match when performing operations that involve multiple pieces of data. When the data types do not match, SQL Server has to...

2019-04-22 (first published: 2019-04-09)

599 reads

Testing with Temporary Stored Procedures

• by Bert Wagner

• Bert Wagner

A while back I learned that it’s possible to create temporary stored procedures in SQL Server. I never put that knowledge into practice however because I struggled to think of...

2019-04-16 (first published: 2019-04-02)

779 reads

4 Reasons To Avoid VARCHAR(8000)

• by Bert Wagner

• Bert Wagner

Watch this week’s episode on YouTubeWhen first learning SQL Server, I had the brilliant idea of defining every column on...

2019-04-05 (first published: 2019-03-19)

1,494 reads

Dipping into the Cookie Jar

• by Bert Wagner

• Bert Wagner

This post is a response to this month’s T-SQL Tuesday #112 prompt by Shane O’Neill.  T-SQL Tuesday is a way for the SQL...

2019-03-29 (first published: 2019-03-12)

274 reads