Background

SQL sublanguage: DDL (Data Definition Language)

The ALTER keyword allows us to add / remove columns and constraints on an existing table.

• Adding a column: ALTER TABLE table_name ADD column_name data_type [constraint];
• Removing a column: ALTER TABLE table_name DROP column_name;

Problem 1

Assume the following table already exists, but is missing a lastname column.

id	firstname
1	Kevin
2	Brian
3	Charles

Write a SQL statement in problem1.sql that adds a lastname column to the site_user table, of type varchar(100).