SUM function
SUM(x) adds all the values in x and returns the total.
SUM function operates on a group of rows and return one row of output.
Null values are ignored by SUM function.
You can use the DISTINCT keyword to exclude duplicate entries.
CREATE TABLE EMP (EMPNO NUMBER(4) NOT NULL,
ENAME VARCHAR2(10),
JOB VARCHAR2(9),
SAL NUMBER(7, 2),
DEPTNO NUMBER(2));
INSERT INTO EMP VALUES (1, 'SMITH', 'CLERK', 800, 20);
INSERT INTO EMP VALUES (2, 'ALLEN', 'SALESMAN', 1600, 30);
INSERT INTO EMP VALUES (3, 'WARD', 'SALESMAN', 1250, 30);
INSERT INTO EMP VALUES (4, 'JONES', 'MANAGER', 2975, 20);
INSERT INTO EMP VALUES (5, 'MARTIN','SALESMAN', 1250, 30);
INSERT INTO EMP VALUES (6, 'BLAKE', 'MANAGER', 2850, 30);
INSERT INTO EMP VALUES (7, 'CLARK', 'MANAGER', 2850, 10);
INSERT INTO EMP VALUES (8, 'SCOTT', 'ANALYST', 3000, 20);
INSERT INTO EMP VALUES (9, 'KING', 'PRESIDENT',3000, 10);
INSERT INTO EMP VALUES (10,'TURNER','SALESMAN', 1500, 30);
INSERT INTO EMP VALUES (11,'ADAMS', 'CLERK', 1500, 20);
SQL> select sum(sal) from emp;
SUM(SAL)
----------
22575
SQL>
Using the SUM function with the group by clause:
SQL> select deptno, SUM(sal) from emp group by deptno;
DEPTNO SUM(SAL)
---------- ----------
30 8450
20 8275
10 5850
SQL>