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
To get employee names starting with A or B listed in order...
select employee_name
from employees
where employee_name LIKE 'A%' OR employee_name LIKE 'B%'
order by employee_name
If you are using Microsoft SQL Server you could use
....
where employee_name LIKE '[A-B]%'
order by employee_name
This is not standard SQL though it just gets translated to the following which is.
WHERE employee_name >= 'A'
AND employee_name < 'C'
For all variants you would need to consider whether you want to include accented variants such as Á
and test whether the queries above do what you want with these on your RDBMS and collation options.