Training guides and resources for learning SQL

Wise Owl provide classroom training in SQL with small course sizes, but for those not fortunate enough to be in the UK we've also published this SQL tutorial online. 

Topics are listed in order of difficulty, so if you've never written a SQL query before you should probably start from the very beginning; otherwise, read down to find the topic you want. 

Background Information

The articles in this section aren't essential in order to successfully write queries in SQL, but you might find some of the information interesting nonetheless.

Getting Started with Queries

This section explains the basics of writing queries in SQL using the SQL Server Management Studio application.

Joins

Many people's least favourite part of writing queries is remembering the code needed to join tables together.  Unfortunately, you'll need to know this if you ever want to use more than one table in a query!

Calculations in SQL

You'll encounter calculations, or expressions, almost everywhere in SQL.  The articles in this section explain everything from simple arithmetic to using complex sequences of nested functions.

Working with Dates in SQL Server

Dates can be one of the most frustrating things to work with in SQL Server, so we thought they deserved a section all to themselves!

Aggregating Data

This section teaches you how to group records together in order to calculate aggregate statistics such as the sum and average of a range of numbers.

Views

You can create a view in order to avoid having to write a query in SQL.  There are a few disadvantages to doing this however, as the articles in this section will explain.

Exporting the Results of Queries

One major disadvantage of using SQL Server Management studio is that it gives you no way to format the results of your queries.  This section explains how you can get your query results into another application so that you can make them look pretty!

Subqueries

A subquery allows you to nest one query inside another allowing you to do all sorts of interesting things.  You'll have to read the articles to find out what they are!

Programming in SQL

The articles in this section explain some of the fundamental concepts you'll need to get the most out of programming in SQL.  Read these articles to prepare yourself for creating stored procedures.

Stored Procedures

A stored procedure is a set of SQL instructions stored in a database.  This section is designed to get you up to speed with the basics of creating stored procedures.

User Defined Functions

User defined functions are a great way to avoid creating the same calculation over and over again in your queries.

Working with Tables

One of the first articles in this tutorial explained how to create and work with tables using SQL Server Management Studio.  This section explains how to do the same things purely in SQL code!

Transactions

Whenever you write code to modify data it's always handy to have the opportunity to undo your changes.  Transactions provide you with exactly that.

Temporary Tables and Table Variables

There are all sorts of ways of working with temporary data in SQL Server.  Below are two main techniques, with an analysis of the pros and cons of each.

Table-Valued Functions

You can use table-valued functions to return sets of rows (usually satisfying some given criteria), which can then be manipulated and joined just like any other table:

CTEs and Derived Tables

Common Table Expressions are a cool successor to derived tables, which allow you to write SQL which is easier to understand:

Pivoting Data

If you've used crosstab queries in Microsoft Access or pivot tables in Microsoft Excel you'll definitely want to know about how to pivot data in SQL Server.

Triggers

Triggers are special stored procedures that are attached to tables.  They are executed automatically when data is inserted, edited or deleted in the table they are attached to.

Cursors

A cursor allows you to step over a set of records one-by-one.  You'll rarely need to use them in SQL Server but this article explains how they work for the rare occasions you do.

Dynamic SQL

Dynamic SQL allows you to build up a string of text and then execute it as a SQL statement.  It allows you to create immensely flexible statements but with one major downside.

One final thought - if you've enjoyed doing any of the tutorials but would prefer classroom SQL training, have a look at our SQL training courses.