i want to display the employee names which having names start with a and b ,it should be like list will display employees with \'a\' as a first letter and then the \'b\' as a
What cfengineers said, except it sounds like you will want to sort it as well.
select columns from table where ( column like 'a%' or column like 'b%' ) order by column
Perhaps it would be a good idea for you to check out some tutorials on SQL, it's pretty interesting.