Need help in writing mssql query : I am having a table having data .. percentage of each students in a school with  below columns ...
**Class | name | Percentage( % ) **  
I need a sql query to get Count of students in each class with below Diff % slabs.Students who had not written exam will have NULL in source table.

class| 0-10% | 10%-20% | 20%-30% | >30% | Not written ( NULLS in source table)


Can anybody help me in writing query .Thanks in advance
  