A Primer on SQL


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A Primer on SQL

Third Edition

About the Book

An introduction to the basics of SQL. No prior experience with SQL is necessary, but some knowledge of working with computers in general is required. My purpose of writing this was to provide a gentle tutorial on the syntax of SQL, so that the reader is able to recognize the parts of queries they encounter and even be able to write simple SQL statements and queries themselves. The book however is not intended as a reference work or for a full time database administrator since it does not have an exaustive topic coverage.

About the Author

Rahul Batra
Rahul Batra

Rahul Batra was first introduced to programming in 1996 in GWBASIC, but he did not seriously foray into it till 2001 when he started learning C++. Along the way, there were dabblings in many other languages like C, Ruby, Perl and Java. He has worked on Oracle, MySQL, Sybase ASA, Ingres and SQLite.

Rahul has been programming professionally since 2006 and currently lives and works in Gurgaon, India.

Table of Contents

  • Preface
  • About the author
  • Acknowledgements
  • 1. An Introduction to SQL
    • 1.1 SQL Commands Classification
    • 1.2 Explaining Tables
  • 2. Getting your database ready
    • 2.1 Using Ingres
    • 2.2 Using SQLite
    • 2.3 Creating your own database
    • 2.4 Table Creation
    • 2.5 Inserting data
    • 2.6 Writing your first query
  • 3. Constraints
    • 3.1 Selective fields INSERT
    • 3.2 Primary Key Constraint
    • 3.3 Unique Key Constraint
    • 3.4 Differences between a Primary Key and a Unique Key
  • 4. Operations on Tables
    • 4.1 Dropping Tables
    • 4.2 Creating new tables from existing tables
    • 4.3 Modifying tables
    • 4.4 Verifying the result in Ingres
    • 4.5 Verifying the result in other DBMS’s
    • 4.6 Showing table information in SQLite
  • 5. Writing Basic Queries
    • 5.1 Selecting a limited number of columns
    • 5.2 Ordering the results
    • 5.3 Ordering using field abbreviations
    • 5.4 Putting conditions with WHERE
    • 5.5 Combining conditions
  • 6. Manipulating Data
    • 6.1 Inserting NULL’s
    • 6.2 Inserting data into a table from another table
    • 6.3 Updating existing data
    • 6.4 Deleting data from tables
  • 7. Organizing your data
    • 7.1 Normalization
    • 7.2 Atomicity
    • 7.3 Repeating Groups
    • 7.4 Splitting the table
  • 8. Doing more with queries
    • 8.1 Counting the records in a table
    • 8.2 Column Aliases
    • 8.3 Order of execution of SELECT queries
    • 8.4 Using the LIKE operator
  • 9. Calculated Fields
    • 9.1 Mathematical calculations
    • 9.2 String operations
    • 9.3 Literal Values
  • 10. Aggregation and Grouping
    • 10.1 Aggregate Functions
    • 10.2 Using DISTINCT with COUNT
    • 10.3 Using MIN to find minimum values
    • 10.4 Grouping Data
    • 10.5 The HAVING Clause
  • 11. Understanding Joins
    • 11.1 What is a Join?
    • 11.2 Alternative Join Syntax
    • 11.3 Resolving ambiguity in join columns
    • 11.4 Cross Joins
    • 11.5 Self Joins
  • 12. Subqueries
    • 12.1 Types of subqueries
    • 12.2 Using subqueries in INSERT statements
  • Further Reading
  • Appendix: Major Database Management Systems
  • Glossary

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