We are excited to announce the general availability of Virtual Network (VNet) Service Endpoints for Azure SQL Database in all Azure regions. This ability allows you to isolate connectivity to your logical server from only a given subnet or set of subnets within your virtual network. The traffic to Azure SQL Database from your VNet will always stay within the Azure backbone network. This direct route will be preferred over any specific routes that take Internet traffic through virtual appliances or on-premises.
There is no additional billing for virtual network access through service endpoints. Current pricing model for Azure SQL DB applies as is.
Read about it in the Azure blog.