# 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.

5 (1)

2020-06-23

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2020-06-22

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2020-06-01

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2020-05-28

# 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.

5 (1)

2019-05-29 (first published: )

# 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.

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2019-05-22 (first published: )

# 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.

3.67 (3)

2019-05-08 (first published: )

# Stairway to T-SQL DML Level 12: Using the MERGE Statement

The final level of this stairway looks at the MERGE statement in detail, focusing on how to perform insert, update and delete logic using the MERGE statement.

2019-03-26 (first published: )

# Stairway to T-SQL DML Level 3: Implementing a Relational Model in SQL Server

This level of the stairway details the creation of a relational database, as well as filling in some of the history of the relational database model.

2019-03-26 (first published: )

# Stairway to T-SQL: Beyond The Basics Level 1: The TOP Clause

The first topic in this stairway will be discussing the TOP clause. The TOP clause allows you to control the number of rows to be returned or affected by a query.

5 (1)

2019-03-26 (first published: )

## Blogs

### Daily Coping 18 Aug 2022

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

### New parameter in sp_DBPermissions and sp_SrvPermissions: @CopyTo

I’ve added a new parameter to my permissions scripts (well, just the main two...

### Creating TAIL on Windows for Text Files

UPDATE: Article changed based on the comment from Mr. Sewell. I wrote recently about...

## Forums

### How to use PowerShell to set secure SA passwords for bulk servers

By Vincent92

Comments posted to this topic are about the item How to use PowerShell to...

### INSERT EXEC statement cannot be nested, the Simple Solution

By Daniel Brink

Comments posted to this topic are about the item INSERT EXEC statement cannot be...

### Cleaning Tables

By Steve Jones - SSC Editor