WE ARE USING SAM , DO WE ALSO NEED TO PURCHASE LICENSE FOR APPINSIGHT FOR SQL

Welcome iosman123​ if you already have a SAM licence then your good to go. The AppInsight templates are just like super versions of the standard templates that consume a set number of components even though they provide much more detail.

AppInsight for SQL will consume 50 components PER INSTANCE on your SQL Server.

To learn more about SAM licensing, see SAM licensing model and SAM Licensing FAQs.