SQL: Visual QuickStart Guide

Introduction

SQL is the standard programming language for creating, updating, and retrieving information that is stored in relational database management systems (DBMSes). With SQL, you can turn your ordinary questions (“Where do our customers live?”) into statements that your database software can understand (SELECT city, state FROM customers;). You may already know how to extract this type of information by using a graphical query tool, but perhaps you’ve noticed that this tool becomes limiting and cumbersome as your questions grow in complexity—that’s where SQL comes in.

You also can use SQL to add, change, and delete data and database objects. Most popular DBMSes—Microsoft Access, Oracle, and MySQL, for example—support SQL, although the level ...