Learning SQL
暫譯: 學習 SQL

Description:

SQL (Structured Query Language) is a standard programming language for generating, manipulating, and retrieving information from a relational database. If you're working with a relational database--whether you're writing applications, performing administrative tasks, or generating reports--you need to know how to interact with your data. Even if you are using a tool that generates SQL for you, such as a reporting tool, there may still be cases where you need to bypass the automatic generation feature and write your own SQL statements.

To help you attain this fundamental SQL knowledge, look to Learning SQL, an introductory guide to SQL, designed primarily for developers just cutting their teeth on the language.

Learning SQL moves you quickly through the basics and then on to some of the more commonly used advanced features. Among the topics discussed:

• The history of the computerized database
  
• SQL Data Statements--those used to create, manipulate, and retrieve data stored in your database; example statements include select, update, insert, and delete
  
• SQL Schema Statements--those used to create database objects, such as tables, indexes, and constraints
  
• How data sets can interact with queries
  
• The importance of subqueries
  
• Data conversion and manipulation via SQL's built-in functions
  
• How conditional logic can be used in Data Statements

Best of all, Learning SQL talks to you in a real-world manner, discussing various platform differences that you're likely to encounter and offering a series of chapter exercises that walk you through the learning process. Whenever possible, the book sticks to the features included in the ANSI SQL standards. This means you'll be able to apply what you learn to any of several different databases; the book covers MySQL, Microsoft SQL Server, and Oracle Database, but the features and syntax should apply just as well (perhaps with some tweaking) to IBM DB2, Sybase Adaptive Server, and PostgreSQL.

Put the power and flexibility of SQL to work. With Learning SQL you can master this important skill and know that the SQL statements you write are indeed correct.

 

Table of Contents:

Preface

1. A Little Background

     Introduction to Databases

     What Is SQL?

     What Is MySQL?

     What's in Store

2. Creating and Populating a Database

     Creating a MySQL Database

     Using the mysql Command-Line Tool

     MySQL Data Types

     Table Creation

     Populating and Modifying Tables

     When Good Statements Go Bad

     The Bank Schema

3. Query Primer

     Query Mechanics

     Query Clauses

     The select Clause

     The from Clause

     The where Clause

     The group by and having Clauses

     The order by Clause

     Exercises

4. Filtering

     Condition Evaluation

     Building a Condition

     Condition Types

     NULL: That Four-Letter Word

     Exercises

5. Querying Multiple Tables

     What Is a Join?

     Joining Three or More Tables

     Self-Joins

     Equi-Joins Versus Non-Equi-Joins

     Join Conditions Versus Filter Conditions

     Exercises

6. Working with Sets

     Set Theory Primer

     Set Theory in Practice

     Set Operators

     Set Operation Rules

     Exercises

7. Data Generation, Conversion, and Manipulation

     Working with String Data

     Working with Numeric Data

     Working with Temporal Data

     Conversion Functions

     Exercises

8. Grouping and Aggregates

     Grouping Concepts

     Aggregate Functions

     Generating Groups

     Group Filter Conditions

     Exercises

9. Subqueries

     What Is a Subquery?

     Subquery Types

     Noncorrelated Subqueries

     Correlated Subqueries

     When to Use Subqueries

     Subquery Wrap-up

     Exercises

10. Joins Revisited

     Outer Joins

     Cross Joins

     Natural Joins

     Exercises

11. Conditional Logic

     What Is Conditional Logic?

     The Case Expression

     Case Expression Examples

     Exercises

12. Transactions

     Multiuser Databases

     What Is a Transaction?

13. Indexes and Constraints

     Indexes

     Constraints

A. ER Diagram for Example Database

B. MySQL Extensions to the SQL Language

C. Solutions to Exercises

D. Further Resources

Index