Introduction to SQL

A new section of each course starts monthly. If enrolling in a series of two or more courses, please be sure to space the start date for each course at least two months apart.

All courses run for six weeks, with a two-week grace period at the end. Two lessons are released each week for the six-week duration of the course. You do not have to be present when lessons are released. You will have access to all lessons until the course ends. However, the interactive discussion area that accompanies each lesson will automatically close two weeks after the lesson is released. As such, we strongly recommend that you complete each lesson within two weeks of its release.

The final exam will be released on the same day as the last lesson. Once the final exam has been released, you will have two weeks to complete all of your course work, including the final exam.

Lesson 1
In our first lesson, we'll explore the basic structure and history of relational databases. Then, you'll understand what SQL is and how it is used with a relational database.

Lesson 2
In this lesson, you'll learn how to use SQL to sort and retrieve data from tables. We'll talk about important query terms that enable you to communicate with your database, as well as syntax rules that will enable you to create clear and understandable queries while avoiding system generated errors.

Lesson 3
In this lesson, you'll learn how to use SQL to filter retrieved data. You'll practice sorting retrieved data using the ORDER BY clause. You'll be able to sort single and multiple columns, and you'll know how to specify sort directions such as ascending and descending order. You'll also learn additional query terms that will help you customize your SQL queries.

Lesson 4
Today, you'll learn how to reformat retrieved data with calculated fields and functions. You'll also learn how to create alternate names for columns and you'll discover the secret behind merging columns with the concatenation symbol.

Lesson 5
In this lesson, we'll discuss gathering significant statistics from data using aggregate functions. You'll also learn how to use the GROUP BY clause in conjunction with an aggregate function to gather important statistics from a table. Then you'll find out how to use the HAVING clause in conjunction with an aggregate function to filter groups of data from a table.

Lesson 6
Today's lesson is all about subqueries. You'll learn how to extract data from multiple tables simultaneously, how to use calculated fields in subqueries, how to use the DATEPART () function in subqueries, and how to use aggregate functions in subqueries. Then we'll talk about qualification—a technique used to combine a table name with a column name so there's no question about which table the column name refers to.

Lesson 7
In this lesson, you'll learn how to use joins to gather information from two or more tables simultaneously. You'll learn how to use the inner join, self-join, natural join, and the outer join. Then you'll become familiar with the term Cartesian product.

Lesson 8
In today's lesson, you'll discover how to manipulate data using the INSERT, UPDATE, and DELETE statements. You'll learn how to insert partial and complete rows into a table, and how to update information already stored in a table. You find out how to transfer data to a new table, how to transfer data to an existing table, and how to delete rows from a table.

Lesson 9
Today, you'll find out how SQL can be used to create and maintain tables. You'll learn how to use the CREATE TABLE keywords to create a table, then we'll discuss how to use the ALTER TABLE, DROP TABLE, ADD COLUMN, and DROP COLUMN keywords to manipulate the tables themselves. You'll also find out how to define a primary key, data type, and field size.

Lesson 10
In this lesson, you'll learn how and why views are used in SQL. You'll learn how to create and use views to simplify complex queries, summarize data, and manipulate data stored in tables. I'll also teach you how to update and delete a view.

Lesson 11
Today, you'll learn how transaction processing, constraints, and indexes are implemented in SQL. You'll work through an example that demonstrates how a transaction is created, how constraints are used in the creation of a table, and how indexes are used to improve the performance of a database by optimizing the speed at which queries are processed.

Lesson 12
In our last lesson, you'll find out how stored procedures, triggers, and cursors are implemented in SQL. You'll see how stored procedures are created and executed, as well as how triggers work. You'll also see how cursors are declared in SQL.