游标或处理程序声明后的变量或条件声明 SQL 语句 (mysql)答案

【问题标题】：Variable or condition declaration after cursor or handler declaration SQL Statement (mysql)游标或处理程序声明后的变量或条件声明 SQL 语句 (mysql)
【发布时间】：2019-06-03 05:00:14
【问题描述】：

即使我尝试了很多事情，它仍然给我这个错误（游标或处理程序声明后的变量或条件声明 SQL 语句）

sp 必须使用游标

CREATE PROCEDURE monthly_sum (IN cardId INT(36), IN monthN INT, OUT sumV float)
BEGIN
DECLARE cursor_1 CURSOR FOR
SELECT SUM(purchased.amountPurchased)
FROM purchased
WHERE MONTH(purchased.dateUsed) = monthN AND purchased.purchasedCardId = cardId AND DAY(purchased.dateUsed) <=10;

DECLARE cursor_2 CURSOR FOR
SELECT SUM(purchased.amountPurchased)
FROM purchased
WHERE MONTH(purchased.dateUsed)  = monthN AND purchased.purchasedCardId = cardId AND DAY(purchased.dateUsed) <=20 AND DAY(purchased.dateUsed) >10;

DECLARE cursor_3 CURSOR FOR
SELECT SUM(purchased.amountPurchased)
FROM purchased
WHERE MONTH(purchased.dateUsed) = monthN AND purchased.purchasedCardId = cardId AND DAY(purchased.dateUsed) >20;

DECLARE percentage1, percentage2, percentage3 float default 0;

OPEN cursor_1;
FETCH cursor_1
INTO percentage1;
CLOSE cursor_1;

OPEN cursor_2;
FETCH cursor_2
INTO percentage2;
CLOSE cursor_2;

OPEN cursor_3;
FETCH cursor_3
INTO percentage3;
CLOSE cursor_3;
SET sumV = percentage1*0.01 + percentage2*0.02 + percentage1*0.03;

SELECT sumV;
END

预期产出是前 10 天的 1%、接下来 10 天的 2%、当月其余天的 3% 之和

【问题讨论】：

你有没有重置 MySQL 默认分隔符.. 比如DELIMITER //
尝试在开头添加这个：DECLARE percent1, percent2, percent3 float default 0;

标签： mysql sql stored-procedures cursor mysql-workbench

【解决方案1】：

我添加了 DECLARE percent1, percent2, percent3 float default 0;一开始就像 karmens89 评论我，它起作用了

【讨论】：

【解决方案2】：

您可以使用select into，而不是不必要地调用光标。由于游标用于逐行获取，但在您的情况下它只会产生一次。

CREATE PROCEDURE monthly_sum (IN cardId INT(36), IN monthN INT, OUT sumV float)
BEGIN

DECLARE percentage1, percentage2, percentage3 float default 0;

SELECT SUM(purchased.amountPurchased) INTO percentage1
FROM purchased
WHERE MONTH(purchased.dateUsed) = monthN 
AND purchased.purchasedCardId = cardId 
AND DAY(purchased.dateUsed) <=10;

SELECT SUM(purchased.amountPurchased) INTO percentage2
FROM purchased
WHERE MONTH(purchased.dateUsed)  = monthN 
AND purchased.purchasedCardId = cardId 
AND DAY(purchased.dateUsed) <=20 AND DAY(purchased.dateUsed) >10;

SELECT SUM(purchased.amountPurchased) INTO percentage3
FROM purchased
WHERE MONTH(purchased.dateUsed) = monthN 
AND purchased.purchasedCardId = cardId 
AND DAY(purchased.dateUsed) >20;

SET sumV = percentage1*0.01 + percentage2*0.02 + percentage1*0.03; # I think percentage3 to be added instead of percentage1
END

【讨论】：