For horizontal-bar chart set type to bar.
Example:
<CHART width="750" height="400" >
<SERIES>
<S type="bar" x="lastname" y="sales"/>
</SERIES>
<SQL>
select first 10 * from (
select e.firstname, e.lastname, sum(o.itemstotal) sales
from customer c join orders o on o.custno=c.custno
join employee e on e.empno=o.empno
group by 1, 2
order by 3 desc
)
</SQL>
</CHART>
Result:
