Invalid Identifier When Trying to Use Package Function in Summation Expression - sql

Question

I'm trying to use the sum function with a package function but running into an "invalid identifier" bug. Here's some example code with the error causing function commented
create or replace type numType as object
(
myNum number
)
;
/
create or replace type numTypes is table of numType;
/
create or replace package testNumberPackage as
function ReturnNum(in_numType numType) return number;
end;
/
create or replace package body testNumberPackage as
function ReturnNum(in_numType numType) return number is
begin
return in_numType.myNum;
end;
end;
/
declare l_numTypes numTypes;
l_count number;
begin
l_numTypes := numTypes();
for i in 1 .. 100 loop
l_numTypes.extend(1);
l_numTypes(l_numTypes.last) := numType(i);
end loop;
select sum(n.myNum) into l_count from table(l_numTypes) n;
select sum(testNumberPackage.ReturnNum(n)) into l_count from table(l_numTypes) n; --causes the error
dbms_output.put_line(l_count);
end;
/
The exact error for this code is
ORA-06550: line 11, column 42
PL/SQL: ORA-00904: "N": invalid identifier
ORA-6550: line 11, column 3:
PL/SQL: SQL Statement ignored
Thanks for any help.

Answer 1

The first issue is that you can't pass a table into a parameter by using its alias. It doesn't even make sense to try doing that.
The next issue is how to get the column mynum that is returned from the table(l_numTypes) into the correct format to pass into testNumberPackage.ReturnNum, since it's of NUMBER datatype, and the function is expecting a numtype parameter.
To do that, you need to pass in an object with that column, like so: numtype(n.mynum).
The following works for me:
declare
l_numTypes numTypes;
l_count number;
begin
l_numTypes := numTypes();
for i in 1 .. 100 loop
l_numTypes.extend(1);
l_numTypes(l_numTypes.last) := numType(i);
end loop;
select sum(n.myNum) into l_count from table(l_numTypes) n;
select sum(testNumberPackage.ReturnNum(numtype(n.mynum))) into l_count from table(l_numTypes) n; --causes the error
dbms_output.put_line(l_count);
end;
/
5050
Clear as mud?