Oracle stored procedure combine results - stored-procedures

Question

I am working on the following Oracle (PL/SQL) stored procedure:
Procedure myProc(idParam IN Number, RESULT OUT SYS_REFCURSOR)
IS
BEGIN
FOR myMetaData in (select status, idData from Table1 where id=idParam)
LOOP
IF myMetaData.status='test1'
SELECT column1, column2, column3 from Table2 where cond1=cond2;
ELSE
SELECT column1, column2, column3 from Table2 where column4=
(select column4 from.....);
END IF;
END LOOP;
END myProc;
Assuming above is my code now I need to return combined results from both IF clause select statement and Else clause. I tried with dbms_sql.return_result(); but it didn't help.
How can I combine both result sets and return the value?

Answer 1

There are many ways to achieve your requirement however i would prefer to use a table to achieve your requirement. See below:
--Create a table to hold your result of if clause
Create table Rslt (col1 number,col2 number, col3 number);
/
--Use sysrefcursor to get the final result out of the table
Procedure myProc(idParam IN Number, RESULT OUT SYS_REFCURSOR)
IS
BEGIN
FOR myMetaData in (select status, idData from Table1 where id=idParam)
LOOP
IF myMetaData.status='test1'
insert into rslt SELECT column1, column2, column3 from Table2 where cond1=cond2;
ELSE
insert into rslt SELECT column1, column2, column3 from Table2 where column4=
(select column4 from.....);
END IF;
END LOOP;
Open result for select * from rslt;
END myProc;
Another apporach could be Object Oriented using a Object having table columns. See below:
Create type rslt is object
(col1 number,
col2 number,
col3 number
);
Create type var_rslt is table of rslt ;
Procedure myProc(idParam IN Number, V_RESULT OUT SYS_REFCURSOR)
IS
v_rslt1 var_rslt:=var_rslt();
v_rslt2 var_rslt:=var_rslt();
v_rslt3 var_rslt:=var_rslt();
v_rslt4 var_rslt:=var_rslt();
BEGIN
FOR myMetaData in (select status, idData from Table1 where id=idParam)
LOOP
IF myMetaData.status='test1'
SELECT rslt(column1, column2, column3) bulk collect into v_rslt1 from Table2 where cond1=cond2;
v_rslt2:=v_rslt2 Multiset union all v_rslt1;
ELSE
SELECT rslt(column1, column2, column3) bulk collect into v_rslt13 from Table2 where column4= (select column4 from.....);
v_rslt4:=v_rslt4 multiset union all v_rslt13;
END IF;
END LOOP;
v_rslt2 := v_rslt2 multiset union all v_rslt4;
OPEN V_RESULT FOR SELECT * FROM table( v_rslt2 );
END myProc;
Demo:
Table Preparation:
Create table Table1 (id number, status varchar2(10));
/
Insert into table1 values(1,'test1');
Insert into table1 values(2,'test2');
Create table Table2 (id number,column1 number, column2 number, column3 number);
/
insert into table2 values(1,10,20,30);
insert into table2 values(1,70,60,50);
insert into table2 values(1,20,40,30);
insert into table2 values(2,80,40,20);
insert into table2 values(2,60,20,10);
Create type rslt is object
(col1 number,
col2 number,
col3 number
);
Create type var_rslt is table of rslt ;
Procedure:
CREATE OR REPLACE Procedure myProc(idParam IN Number, V_RESULT OUT sys_refcursor)
IS
v_rslt1 var_rslt:=var_rslt();
v_rslt2 var_rslt:=var_rslt();
v_rslt3 var_rslt:=var_rslt();
v_rslt4 var_rslt:=var_rslt();
BEGIN
FOR myMetaData in (select status, id from Table1)
LOOP
IF myMetaData.status='test1' then
SELECT rslt(column1, column2, column3) bulk collect into v_rslt1 from Table2 where id=myMetaData.id;
v_rslt2:=v_rslt2 Multiset union all v_rslt1;
ELSE
SELECT rslt(column1, column2, column3) bulk collect into v_rslt3 from Table2 where id=myMetaData.id;
v_rslt4:=v_rslt4 multiset union all v_rslt3;
END IF;
END LOOP;
v_rslt4 := v_rslt4 multiset union all v_rslt2;
open V_RESULT for Select * from table(v_rslt4);
END myProc;
Execution:
DECLARE
var sys_refcursor;
var1 NUMBER;
var2 NUMBER;
var3 NUMBER;
BEGIN
myProc(1, var);
LOOP
FETCH var INTO var1,var2,var3;
EXIT WHEN var%notfound;
dbms_output.put_line(var1);
END LOOP;
END;
OUTPUT:
SQL> /
anonymous block completed
80
60
10
70
20
Note: This solution will work on Oracle 11g and onward versions. Incase you are working on lower version of Oracle, then you need to modify the Object definition as below:
Create type rslt is object
(col1 number,
col2 number,
col3 number,
map member function mem return number);
This is due to a bug in Oracle 10g while using MULTISET operator.
Read more about the bug at http://raajeshwaran.blogspot.com/2010/07/pls-00801-internal-error-assert-at-file.html