Useful websites for SQL language training or reference

The ElevateDB Website

This single web-page actually details the whole SQL SELECT statement in a single place, and is a good reference. However it does require the user to have a really clear understanding of how to build statements. Beginners will find it fairly difficult to follow and understand.

General Web-pages

W3 Schools

www.w3schools.com/sql/sql_select.asp

W3 Schools have many of the best resources for learning programming languages.

The link above is for SQL SELECT, but the site includes pages for all aspects of SQL including more advanced topics such as table creation. W3 Schools also cover many other programming languages. Developers working with Orixa systems may find it useful to review their pages on HTML, CSS and XML.

Wikipedia

https://en.wikipedia.org/wiki/SQL

Wikipedia gives a thorough background in the history and function of SQL.

Developers may find some of these pages interesting where they discuss mechanisms for structuring data-systems.