Gregory Larsen

Currently a SQL Server DBA. I've been working with SQL Server since 1999. I'm an old-time mainframe DBA. My DBA career started in 1985. Currently studying to obtaining MCDBA.

Stairway to T-SQL DML

Stairway to T-SQL DML Level 5: The Mathematics of SQL: Part 2

Joining tables is a crucial concept to understanding data relationships in a relational database. When you are working with your SQL Server data, you will often need to join tables to produce the results your application requires. Having a good understanding of set theory, and the mathematical operators available and how they are used to join tables will make it easier for you to retrieve the data you need from SQL Server.

(1)

You rated this post out of 5. Change rating

2019-05-29 (first published: )

18,217 reads

Stairway to T-SQL DML

Stairway to T-SQL DML Level 4: The Mathematics of SQL: Part 1

A relational database contains tables that relate to each other by key values. When querying data from these related tables you may choose to select data from a single table or many tables. If you select data from many tables, you normally join those tables together using specified join criteria. The concepts of selecting data from tables and joining tables together is all about managing and manipulating sets of data. In Level 4 of this Stairway we will explore the concepts of set theory and mathematical operators to join, merge, and return data from multiple SQL Server tables.

(6)

You rated this post out of 5. Change rating

2019-05-22 (first published: )

24,540 reads

Stairway to T-SQL Beyond The Basics

Stairway to T-SQL: Beyond The Basics Level 3: Building a Correlated Subquery

This stairway level will expand on the subquery topic by discussing a type of subquery known as a correlated subquery, and explores what a correlated subquery is and how it is different from a normal subquery.

(3)

You rated this post out of 5. Change rating

2019-05-08 (first published: )

20,569 reads

Blogs

Using Prompt AI for a Travel Data Analysis

By

I was looking back at my year and decided to see if SQL Prompt...

FinOps for Kubernetes: Leveraging OpenCost, KubeGreen, and Kubecost for Cost Efficiency

By

In the era of cloud-native applications, Kubernetes has become the default standard platform for...

2025 Wrapped for Steve

By

I’ve often done some analysis of my year in different ways. Last year I...

Read the latest Blogs

Forums

The North Star for the Year

By Steve Jones - SSC Editor

Comments posted to this topic are about the item The North Star for the...

Multiple Escape Characters

By Steve Jones - SSC Editor

Comments posted to this topic are about the item Multiple Escape Characters

reaching ftp thru winscp but erroring in ssis ftp task connection

By stan

Hi, below i show various results trying to reach our ftp site (a globalscape...

Visit the forum

Question of the Day

Multiple Escape Characters

In SQL Server 2025, I run this code (in a database with the appropriate collation):

SELECT UNISTR('%*3041%*308A%*304C%*3068 and good night', '%*') AS 'A Classic';
What is returned?

See possible answers