Dynamically Generating Charts

Question

I need to be able to generate charts in APEX 3.01 from a SQL query which doesn't exist until it's built at runtime.
The query is of the form:
SELECT null link, x label, count(*) value FROM y table GROUP BY label, value ORDER BY 3 DESC
x and y are the dynamically generated bits. I build the query using a PL/SQL anon block:
DECLARE
myquery VARCHAR2(4000);
BEGIN
myquery := 'select null link,';
myquery := myquery || :P39_MYCHARTQUERY;
myquery := myquery || ' label, count(*) value from ';
myquery := myquery || :P39_MYCHARTTABLE;
myquery := myquery || ' group by label, value';
myquery := myquery || ' order by value desc';
htp.print(myquery);
END;
The problem is, APEX charts will only accept a straight SQL query, not a PL/SQL block. I've tried putting the block into a hidden field (Display as Text, PLSQL version) and referencing it using substitution strings (&variable_name. style), but this doesn't seem to work. APEX is complaining about my generated SQL query:
"Error in rendering chart: ORA-06561: given statement is not supported by package DBMS_SQL"
The SQL looks correct. I have no idea what the problem is. Can anyone help?

Answer 1

That's an interesting blog post. I'll have to dig around in SQL Workshop to see how to implement it. Modifying it to be multi-variable looks like it shouldn't be too difficult. Teaching myself about what packages are and how to use them will be the hard part.