DAX References

Read more about the types of DAX functions: 

• Date and Time Functions 
• Filter Functions
• Information Functions
• Logical Functions
• Mathematical and Trigonometric Functions
• Statistical Functions
• Text Functions
• Time Intelligence Functions
•  Some Additional links

DAX Operator reference:

• Operator Reference
• Appendix DAX Reference

For more resource check:

• DAX Resource Center.
• How filters behave.

For those who want to relate DAX with MDX and SQL, kindly refer the following link:

• Converting MDX to DAX

Adventure Works database:
http://www.ssas-info.com/analysis-services-faq/29-mgmt/242-how-install-adventure-works-dw-database-analysis-services-2005-sample-database