Line chart error

Question

Created a line chart with two series as follows:
Query for series 1
select null, period_no, valuex
(select null, period_no, avg(actual) valuex
from kpi_performance
group by period_by
order by period_by)
Query for series 2
select null, period_no, valuex
(select null, period_no, avg(forecast) valuex
from kpi_performance
group by period_by
order by period_by)
When the page is executed the following error is displayed:
"SVG chart error: ORA-20001: line_chart error: ORA-20001: get_data error:ORA-20001: Parse error: ORA-00936: missing expression"
I think this is related to the use of "group by" and "order by" in the queries but cannot find a workaround.
Any ideas ?
Thanks
Vincent

Answer 1

I believe that the problem may be the ORDER BY. I believe that you cannot have an ORDER BY clause in a series.