I want to create a stored procedure with one argument which will return different sets of records depending on the argument. What is the way to do this? Can I call it from plain SQL?
views:
16911answers:
5I think you want to return a REFCURSOR:
create function test_cursor
return sys_refcursor
is
c_result sys_refcursor;
begin
open c_result for
select * from dual;
return c_result;
end;
Update: If you need to call this from SQL, use a table function like @Tony Andrews suggested.
Probably with the use of table functions. Have a look at this documentation Table Functions and Cursor Expressions
Here is how to build a function that returns a result set that can be queried as if it were a table:
SQL> create type emp_obj is object (empno number, ename varchar2(10));
2 /
Type created.
SQL> create type emp_tab is table of emp_obj;
2 /
Type created.
SQL> create or replace function all_emps return emp_tab
2 is
3 l_emp_tab emp_tab := emp_tab();
4 n integer := 0;
5 begin
6 for r in (select empno, ename from emp)
7 loop
8 l_emp_tab.extend;
9 n := n + 1;
10 l_emp_tab(n) := emp_obj(r.empno, r.ename);
11 end loop;
12 return l_emp_tab;
13 end;
14 /
Function created.
SQL> select * from table (all_emps);
EMPNO ENAME
---------- ----------
7369 SMITH
7499 ALLEN
7521 WARD
7566 JONES
7654 MARTIN
7698 BLAKE
7782 CLARK
7788 SCOTT
7839 KING
7844 TURNER
7902 FORD
7934 MILLER
If you want to use it in plain SQL, I would let the store procedure fill a table or temp table with the resulting rows (or go for @Tony Andrews approach).
If you want to use @Thilo's solution, you have to loop the cursor using PL/SQL.
Here an example: (I used a procedure instead of a function, like @Thilo did)
create or replace procedure myprocedure(retval in out sys_refcursor) is
begin
open retval for
select TABLE_NAME from user_tables;
end myprocedure;
declare
myrefcur sys_refcursor;
tablename user_tables.TABLE_NAME%type;
begin
myprocedure(myrefcur);
loop
fetch myrefcur into tablename;
exit when myrefcur%notfound
dbms_output.put_line(tablename);
end loop;
close myrefcur;
end;
this code is missing a semi-colon, look below:
create or replace procedure myprocedure(retval in out sys_refcursor) is begin open retval for select TABLE_NAME from user_tables; end myprocedure;
declare
myrefcur sys_refcursor;
tablename user_tables.TABLE_NAME%type;
begin
myprocedure(myrefcur);
loop
fetch myrefcur into tablename;
exit when myrefcur%notfound; --<<<< HERE
dbms_output.put_line(tablename);
end loop;
close myrefcur;
end;