1. How to add SOQL in Visualforce page?


Using AJAX in Javascript.


2. How to send parameter from one page to another page in Salesforce?


At the end of the url, you can pass the parameter.


Or


https://infallibletechie.com/2012/01/to-send-parameters-from-one-visualforce.html


3. Write a trigger to roll up sum of amount from opportunities to Account “Total Amount”?

https://infallibletechie.com/2014/03/trigger-to-find-total-opportunity.html


4. How to find users in Schedule Future Runs in Reports in Salesforce if it is not available?


https://infallibletechie.com/2013/04/unable-to-find-users-in-schedule-future.html


5. How code coverage is calculated in Salesforce?


https://infallibletechie.com/2014/05/how-code-coverage-is-calculated-in.html


https://infallibletechie.com/2014/04/how-to-see-overall-code-coverage-in.html

Cheers!!!