Leave Management for approved SP how to do the Logic

Question

Hi,

I am doing Leave Management project in Asp.net c#.

Through Free template i have created Master page ,Employee Details,Role,Department,Leave Type in Admin.

Now when the user will login with valid user id and password then the user can select the leave type dropdown,department dropdown,description,Approver dropdown and from date and todate. After click the submit the data is saved in the database. and through Joining the user can see the details in the gridview in panel view.

Now the mail has to go to approver to approved the leave and the status will show as in pending status in gridview. So what will be my SP to write if it's 0 then status will pending when 1 then approved when 2 then it will reject i the status.

Could you please guide me how to write the SP for this logic.