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: )

1,192 reads

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: )

1,499 reads

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....


195 reads

Window Functions vs GROUP BYs

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: )

1,172 reads

Joining on NULLs

It’s important to be aware of columns that allow NULL values since SQL Server may handle NULLs differently than you might expect. Today I want to look at what...


14 reads


Spark .NET - Spark ML TF-IDF


Spark ML in .NET for Apache Spark Spark is awesome, .NET is awesome, machine...

Daily Coping 7 Jul 2020


I’ve started to add a daily coping tip to the SQLServerCentral newsletter and to...

Publish ADF from code to further environments


Struggling with #ADF deployment? adf_publish branch doesn’t suit your purposes? Don’t have skills with PowerShell? I have good...

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