函数“SUM 不存在”

我正在使用 mysql 5.5.11，当我执行下面的脚本时

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

我收到错误

SQL 错误：FUNCTION mydb.SUM 不存在。检查“函数名称” 参考手册中的“解析和解析”部分

这是表架构

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;

错误的原因可能是什么

这是附加到表的触发器

BEGIN
  /* Trigger text */
  UPDATE Orders Set Paid =(Select SUM (Amount) From Payments AS p Where p.OrderID  = Orders.ID),PayMethod =new.PayMethod  WHere Orders.id = new.OrderID;
   UPDATE Orders Set Bal = Total - Paid  WHere Orders.id = new.OrderID;
END

看触发：

UPDATE Orders Set Paid =(Select SUM (Amount) From Payments AS p Where p.OrderID  = Orders.ID),PayMethod =new.PayMethod  WHere Orders.id = new.OrderID;

MySQL 不接受函数名和括号之间的空格（除非您设置了 SQL_MODE=IGNORE_SPACE，但这会给您带来其他不良副作用）

您可以通过运行以下命令来检查 SQL_MODE 设置：

SHOW GLOBAL VARIABLES LIKE 'SQL_MODE';

关于此的 MySQL 文档：link http://dev.mysql.com/doc/refman/5.5/en/function-resolution.html

一些例子：

mysql> select sum(5);
+--------+
| sum(5) |
+--------+
|      5 |
+--------+
1 row in set (0.00 sec)

mysql> select sum (5);
ERROR 1305 (42000): FUNCTION sum does not exist

解决方案：删除空格

UPDATE Orders Set Paid =(Select SUM(Amount) From Payments AS p Where p.OrderID  = Orders.ID),PayMethod =new.PayMethod  WHere Orders.id = new.OrderID;