Return Multiple Values from Oracle Function - sql

Question

I want to create a function that returns multiple rows into a table that is of object type.
I have created an object and a nested table object and now when I run the function there is an error which says
PL/SQL: SQL Statement ignored
PL/SQL: ORA-00947: not enough values
-- Object type creation
create or replace type test_object_sn as object
(
column_1 varchar2(30),
column_2 varchar2(30),
column_3 number
);
-- Table of object
create or replace type test_otable_sn as table of test_object_sn;
-- function (where I get an error)
create or replace function load_test_object_sn
return test_otable_sn
as
details test_otable_sn;
begin
with ad as (select 'a', 'b', 4 from dual
union all
select 'r', '5', 3 from dual
union all
select 'g', 's', 3 from dual)
select * into details from ad;
return details;
end;
I want to have the test_otable_sn table object loaded with the data and then query it using the table() function via my load_test_object_sn function
e.g. select * from table(load_test_object_sn);

Answer 1

Update:
do you know how to modify this for scenario whereby I have an sql
statement contained in a string variable to execute?
Yes, we can use a cursor reference (SYS_REFCURSOR) and OPEN/FETCH/CLOSE instead of a CURSOR and CURSOR FOR LOOP.
The syntax is OPEN <cursor-reference> FOR <string-containing-sql-statement> . See below.
CREATE OR REPLACE FUNCTION load_test_object_sn
RETURN test_otable_sn
AS
details test_otable_sn := test_otable_sn();
-- Variable stores SQL statement for cursor
l_sql CLOB :=
q'[with ad as (
select 'a' column_1, 'b' column_2, 4 column_3 from dual union all
select 'r', '5', 3 from dual union all
select 'g', 's', 3 from dual
)
select *
from ad]';
-- Cursor reference allows us to open cursor for SQL statement above
rc SYS_REFCURSOR;
-- Define object instance to store each row fetched from the cursor
l_obj test_object_sn := test_object_sn(NULL, NULL, NULL);
i PLS_INTEGER := 1;
BEGIN
-- Explicitly open, fetch from, and close the cursor
OPEN rc FOR l_sql;
LOOP
FETCH rc INTO l_obj.column_1, l_obj.column_2, l_obj.column_3;
EXIT WHEN rc%NOTFOUND;
details.extend();
details(i) := test_object_sn(l_obj.column_1, l_obj.column_2, l_obj.column_3);
i := i + 1;
END LOOP;
CLOSE rc;
RETURN details;
END;
Original answer:
Unfortunately, one can't use SELECT * INTO with a collection in this manner, so here's an alternative way to populate the table:
create or replace function load_test_object_sn
return test_otable_sn
as
details test_otable_sn := test_otable_sn();
cursor c_ad is
with ad as (select 'a' column_1, 'b' column_2, 4 column_3 from dual
union all
select 'r', '5', 3 from dual
union all
select 'g', 's', 3 from dual)
select * from ad;
i pls_integer := 1;
begin
for ad_rec in c_ad loop
details.extend();
details(i) := test_object_sn(ad_rec.column_1, ad_rec.column_2, ad_rec.column_3);
i := i + 1;
end loop;
return details;
end;
/
Output:
SQL> SELECT * FROM TABLE(load_test_object_sn);
COLUMN_1 COLUMN_2 COLUMN_3
---------- ---------- ----------
a b 4
r 5 3
g s 3