Pipelining Between PL/SQL Table Functions - oracle

Question

I have a package with 2 pipelined functions. When I'm trying to call one function with another function as it's argument I'm getting "ORA-06553: PLS-306: wrong number or types of arguments in call" error.
Here is the package:
create or replace NONEDITIONABLE TYPE RESULTING_RECORD_RT as object
(
CALENDAR NVARCHAR2(1024),
PRODUCT NVARCHAR2(1024),
MEASURE NVARCHAR2(1024),
VALUE NUMBER
);
/
create or replace NONEDITIONABLE TYPE RESULTING_COLS_RT IS TABLE OF RESULTING_RECORD_RT;
/
create or replace package pipe_pkg as
function pipe_func_emp return RESULTING_COLS_RT PIPELINED;
function pipe_func_emp2(input_Set IN resulting_cols_rt) return RESULTING_COLS_RT PIPELINED;
end;
/
create or replace package body pipe_pkg as
function pipe_func_emp return RESULTING_COLS_RT
PIPELINED
is
test_tbl resulting_cols_rt:= resulting_cols_rt();
begin
test_tbl.extend;
test_tbl(1):=resulting_record_rt('A','B','C',1);
test_tbl.extend;
test_tbl(2):=resulting_record_rt('A','B','D',2);
PIPE ROW(test_tbl(1));
PIPE ROW(test_tbl(2));
return;
end;
function pipe_func_emp2(input_Set IN resulting_cols_rt) return RESULTING_COLS_RT
PIPELINED
is
v_tmp NVARCHAR2(10240);
l_res SYS_REFCURSOR;
recs resulting_record_rt;
begin
open l_res for select * from table(input_Set);
loop
fetch l_res into recs;
PIPE ROW(recs);
exit when l_res%notfound;
end loop;
close l_res;
return;
end;
end;
/
I'm calling the functions as follows:
select * from TABLE(pipe_pkg.pipe_func_emp2(CURSOR(select * from TABLE(pipe_pkg.pipe_func_emp()))));
And the call throws error:
ORA-06553: PLS-306: wrong number or types of arguments in call to 'PIPE_FUNC_EMP2'
06553. 00000 - "PLS-%s: %s"
What am I doing wrong?

Answer 1

The function pipe_func_emp2 expected RESULTING_COLS_RT as it's argument, but got REF CURSOR. These are incompatible types.
Try following reproducible example of a chaining of the pipelined functions:
create or replace type somerow as object (id int, val varchar2 (8))
/
create or replace type sometab is table of somerow
/
create or replace package pack as
function func1 return sometab pipelined;
function func2 (cur sys_refcursor) return sometab pipelined;
end;
/
create or replace package body pack as
function func1 return sometab pipelined is
tab sometab := sometab (somerow (1,'AAA'), somerow (2,'BBB'));
begin
for i in 1..tab.count loop
pipe row (tab(i));
end loop;
return;
end;
function func2 (cur sys_refcursor) return sometab pipelined is
sr somerow;
begin
loop
fetch cur into sr;
exit when cur%notfound;
pipe row (sr);
end loop;
close cur;
return;
end;
end;
/
The query and it's outcome:
select *
from table (pack.func2 (
cursor (select value (p) from table (pack.func1()) p )))
/
ID VAL
---------- --------
1 AAA
2 BBB