Disclamier : I'm not a SQL Guru, nor DBA but as I saw the document being quoted several times, it should have some revelancy.
Use the index is about best practices on SQL indexations and optimisations and content is both in English and French :
It concerns all main databases : MySQL, Oracle, Postgresql, IBM DB2 and Microsoft SQL Server
CHAPTER 1 - Anatomy of an Index
The first chapter is the only one that doesn’t cover SQL specifically; it is about the fundamental structure of an index. An understanding of the index structure is essential to following the later chapters—don’t skip this!
Although the chapter is rather short—only about eight pages—after working through the chapter you will already understand the phenomenon of slow indexes.
CHAPTER 2 - The Where Clause
This is where we pull out all the stops. This chapter explains all aspects of the where clause, from very simple single column lookups to complex clauses for ranges and special cases such as
This chapter makes up the main body of the book. Once you learn to use these techniques, you will write much faster SQL.
CHAPTER 3 - Performance and Scalability
This chapter is a little digression about performance measurements and database scalability. See why adding hardware is not the best solution to slow queries.
CHAPTER 4 - The Join Operation
Back to SQL: here you will find an explanation of how to use indexes to perform a fast table join.
CHAPTER 5 - Clustering Data
Have you ever wondered if there is any difference between selecting a single column or all columns? Here is the answer—along with a trick to get even better performance.
CHAPTER 6 - Sorting and Grouping
Even order by and group by can use indexes.
CHAPTER 7 - Partial Results
This chapter explains how to benefit from a “pipelined” execution if you don’t need the full result set.
CHAPTER 8 - Insert, Delete and Update
How do indexes affect write performance? Indexes don’t come for free—use them wisely!
APPENDIX A - Execution Plans
Asking the database how it executes a statement.
APPENDIX B - Myth Directory
Lists some common myth and explains the truth. Will be extended as the book grows.
APPENDIX C - Example Schema
All create and insert statements for the tables from the book.
So you can read the book online or buy it