Userul resources and free online books for PHP, MySql, jQuery, JavaScript

Most useful resource  for PHP, MySql, jQuery, JavaScript:
http://www.w3schools.com/

PHP programming:
 http://en.wikibooks.org/wiki/PHP_Programming

Eloquent JavaScript
http://eloquentjavascript.net/

JavaScript Guide:
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide

Speaking JavaScript:
http://speakingjs.com/es5/

DOM
http://domenlightenment.com/

jQuery fundamental:
http://jqfundamentals.com/

Learn jQuery:
http://learn.jquery.com/

Pro Git:
http://git-scm.com/book/en/v2

Learn Git:
https://www.git-tower.com/learn/ebook

Essential SQL:
http://www.essentialsql.com/getting-started/

SQL at StandFord:
https://class.stanford.edu/courses/DB/SQL/SelfPaced/courseware/ch-sql/seq-vid-introduction_to_sql/

SQL for Web nerds:
http://philip.greenspun.com/sql/

SQL Zoo:
http://sqlzoo.net/wiki/Main_Page

HTML and CSS:
http://learn.shayhowe.com/html-css/