SUM Function does not exists

[oghenero Enegede]

I am using mysql 5.5.11, when i execute the script below

INSERT INTO payments(created, Amount, user, Remarks, orderid, paymethod)
VALUES('2016-09-03', 0.0, 'admin', '', 4, 'Cash');

I get error

SQL Error: FUNCTION mydb.SUM does not exist. Check the 'Function Name Parsing and Resolution' section in the Reference Manual


This is the table schema

CREATE TABLE payments (
ID int AUTO_INCREMENT NOT NULL,
OrderID int,
Amount decimal(11,2),
Created varchar(20),
Remarks varchar(160),
user varchar(60),
PayMethod varchar(60) CHARACTER SET utf8 COLLATE utf8_general_ci,
/* Keys */
PRIMARY KEY (ID)
) ENGINE = InnoDB;