SQL Notes

• A Visual Explanation of SQL Joins

• Understanding Explain Select Statement Results
• MySQL 3.23, 4.0, 4.1 Reference Manual
• MySQL 5.1 Reference Manual

• Oracle Technology Network

• Producing and Reading Explain Plans

To produce an Explain Plan:

explain plan set statement_id = '<SOME_IDENTIFIER>' for
/* ------ Your SQL here ------ */

To read an Explain Plan:

select operation, options, object_name
  from plan_table
 where statement_id = '<SOME_IDENTIFIER>'
start with id = 0
connect by prior id=parent_id and prior statement_id = statement_id;