Stairway to SQL Server Extended Events

Stairway to SQL Server Extended Events Level 4: Extended Events Engine - Essential Concepts

In this level, we're going to dig a little deeper into the Extended Events engine, its architecture, and fundamental components. It will give you a deeper understanding of why, in general, an Extended Events session is inherently lower in overhead than an equivalent SQL Trace. We'll also investigate how to design our event sessions to minimize any unnecessary overhead during event data collection, even when we need to create relatively complex event sessions to investigate difficult performance problems.

Stairway to T-SQL Beyond The Basics

Stairway to T-SQL: Beyond The Basics Level 4: Using Views to Simplify Your Query

This level discusses how to use a database VIEW to simplify your Transact-SQL(T-SQL) code. By understanding how to use a VIEW you will be able to better support writing T-SQL code to meet complex business requirements. In this article I will be discussing what a database VIEW is and then providing a number of examples to help you understand how you can use a VIEW to implement different coding scenarios.

Stairway to T-SQL Beyond The Basics

Stairway to T-SQL: Beyond The Basics Level 6: Using the CASE Expression and IIF Function

There are times where you need to write a single T-SQL statement that is able to return different T-SQL expressions based on the evaluation of another expression. When you need this kind of functionality you can use the CASE expression or IIF function to meet this requirement. In this Stairway level Gregory Larsen reviews the CASE and IIF syntax and showing you examples of how the CASE expression and IIF function.

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Question of the Day

Getting the Average

I have this data in the dbo.Commission table in a SQL Server 2022 database. 

salesperson commission
Brian       12
Brian       16
Andy        7
Andy        14
Andy        21
Steve       20
Steve       NULL
All the data is a varchar, and I decide to run this query to get the totals for each salesperson. 
SELECT SalesPerson
     , AVG(TRY_PARSE(Commission AS int)) AS TotalCommission
 FROM commission
 GROUP BY SalesPerson
GO
What average commission is calculated for Steve?

See possible answers