mysql - 使用 mysql 用户定义函数来计算美元金额。错误 1064 (42000)

Question

我正在尝试创建一个 mysql 函数来计算商店中前五名顾客的总支出，但我不断收到以下语法错误。是什么导致了错误？ 错误:

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that
corresponds to your MySQL server version for the right syntax to use near
'FUNCTION costofbestbuyers (totalspent DECIMAL)
RETURNS DOUBLE
BEGIN
    DECLA' at line 1

功能:

DELIMITER // 
CREATE FUNCTION topfivespenders (totalspent DECIMAL) 
RETURNS DOUBLE 
BEGIN 
    DECLARE totalspent DOUBLE DEFAULT 0; 

    SELECT sum(ordercost) AS totalspent
      FROM customer c JOIN orders o 
      ON c.customerID = o.cID 
      GROUP BY o.cID 
      ORDER BY totalspent desc 
      LIMIT 5; 

RETURN totalspent; 
END; //

Answer 1

将 sum(ordercost) 值设置为 totalspent 变量的语法不正确。

试试这个。希望这有效。

DELIMITER // 
CREATE FUNCTION topfivespenders (totalspent DECIMAL) 
RETURNS DOUBLE 
BEGIN 
    DECLARE totalspent DOUBLE DEFAULT 0; 

    SELECT sum(ordercost) INTO totalspent
      FROM customer c JOIN orders o 
      ON c.customerID = o.cID 
      GROUP BY o.cID 
      ORDER BY totalspent desc 
      LIMIT 5; 

RETURN totalspent; 
END//
DELIMITER //