@Anusha Rudra I do see Sharepoint does have the client library for the basic operation and for Azure SQL I can see Azure SQL Database APIs for .NET which you can explore and see if it can help you with your scenario/use case. If not you can check if there are any REST APIs or any other service SDK that you can leverage to perform the operations.
From the function perspective, we don't have any Sharepoint trigger function but you can leverage any of the existing triggers (HTTP or Timmer) to execute your function app. Your function app code leverages any existing SDKs or the service REST APIs to perform the operation. Your function app will only have the input binding with no output bindings as you will be using Azure SQL Database APIs for .NET to write the data.