How to use sum() function inside stored procedure in oracle? - oracle

Question

The example below works fine and it return some rows. But I need summary of the rows.
DECLARE
x number;
Cursor c1 is
select sal,deptno from emp;
rw c1%rowtype;
BEGIN
x:=0;
open c1;
LOOP
fetch c1 into rw;
FOR i IN 1..rw.deptno LOOP
x:=x+rw.sal;
end loop;
exit when c1%notfound;
DBMS_OUTPUT.PUT_LINE(x);
END LOOP;
close c1;
END;
/
Suppose you have three employees and every employee's has different salary. The salary has due for 10 months and 20 months and 30 months. The salary is due for long time. So you want to add 2% bonus amount with salary for every month as the way:
The below description is for single Employee for 10 months:
Month-1 Salary = 800 => 800*2% = 16.00 => Total = 800+16 =816
Month-2 Salary = 816 => 816*2% = 16.32 => Total = 816+16.32 =832.32
............................................................................
Month-10 Salary = 956.07 => 956.07*% = 19.12 => Total = 956.07+19.12 =975.20
The Months-1 Total Salary=816. So Month-2 Salary=816. This will continue up 10 months.Every Employee has the same condition. So I need summary of the total column. Thanks and best regards.

Answer 1

When you use aggregate function SUM in your query (unlike, when you adding yourself), you don't need to convert NULL. SUM takes care of it. Although, as #DavidAldridge pointed, if you expect that all rows in summarized group of records may contain NULL, your sum will also be NULL. If you want to return a value, you can wrap your sum as follows coalesce(sum(sal),0)
This will give you SUM of all salaries
select SUM(sal) TotalSal from emp;
This will give you SUM by department
select SUM(sal) TotalDeptSal, deptno
from emp
group by deptno;
In you question you posted that you need to execute it in stored procedure while your code as an anonymous block. If you want to return single value from Stored procedure you have a choice to declare function with return parameter or stored procedure with output parameter. To return a recordset from stored procedure in Oracle you need to declare a refcursor output parameter
CREATE OR REPLACE PROCEDURE Get_TotalSal_ByDept (
p_recordset OUT SYS_REFCURSOR) AS
BEGIN
OPEN p_recordset FOR
select SUM(sal) TotalDeptSal, deptno
from emp
group by deptno;
END;
Edit
I see that you added row - total. It is not changing much from the original question. Still, using cursor is not needed. You can run 2 queries and return 2 output parameters, one with data by department and another is total.
CREATE OR REPLACE PROCEDURE Get_SalByDept_WithTotal (
p_total OUT NUMBER,
p_recordset OUT SYS_REFCURSOR) AS
BEGIN
select SUM(sal) INTO p_total from emp;
OPEN p_recordset FOR
select SUM(sal) TotalDeptSal, deptno
from emp
group by deptno;
END;

Answer 2

Is this what you looking for? The Running totals?
SELECT totals.deptNo, totals.depttotal, SUM(totals.depttotal) OVER (ORDER BY totals.id)
FROM (
select deptNo, deptTotal, rownum id
from (
select deptNo, sum(sal * deptNo) deptTotal
from emp
group by deptNo)
) totals
ORDER BY totals.id;
If you have some sort of department Id you can use that instead of artificially generated one from ROWNUM