游标或处理程序声明SQL语句（mysql）后的变量或条件声明

即使我尝试了很多方法，它仍然会给我这个错误（游标或处理程序声明之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

创建程序月度金额（卡内整数（36）、月内整数、月外浮动）
开始
声明游标\u 1游标用于
选择金额（已购买。已购买金额）
从购买
其中月（购买.日期使用）=月，购买.购买D=卡，日（购买.日期使用）20；
声明percentage1、percentage2、percentage3浮动默认为0；
打开光标_1；
取光标_1
分为百分比1；
关闭光标_1；
打开光标2；
取光标2
分为百分比2；
关闭光标_2；
打开光标3；
取光标_3
分为3个百分点；
关闭光标_3；
设置sumV=percentage1*0.01+percentage2*0.02+percentage1*0.03；
选择sumV；
结束

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预期输出前10天的1%，后10天的2%，当月剩余天数的3%的总和

我添加了DECLARE percentage1，percentage2，percentage3浮动默认值0；开始时，就像karmens89评论我一样，它工作了

而不是不必要地调用游标，您可以使用

选择进入

。因为游标用于逐行获取数据，但在您的情况下，它只会产生一次结果

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

创建程序月度金额（卡内整数（36）、月内整数、月外浮动）
开始
声明percentage1、percentage2、percentage3浮动默认为0；
选择百分比1中的金额（已购买.已购买金额）
从购买
其中月份（购买日期使用）=月份
和已购买。purchasedCardId=cardId
第20天（购买日期和使用日期）；
设置sumV=percentage1*0.01+percentage2*0.02+percentage1*0.03；#我认为应该增加百分比3，而不是百分比1
结束

您是否重置了MySQL默认分隔符。。像

分隔符//

一样，尝试在开头添加以下内容：声明percentage1、percentage2、percentage3浮动默认值0；