you havent mentioned any code so we have fair idea of your data's. but with that knowledge a sample query may be help you to get going.
you need to write a select query with where condition to filter out the matching employee name. if filter is empty select all.
select * from employeeTable; // this query will return all the rows inside the table employeeTable
select * from employeeTable where EmployeeName = txtFromCombo; // this will return row that matching the EmployeeName equals to the value txtFromCombo where txtFromCombo is a string.