使用if語句更新表

Question

我試圖用這個命令用IF語句來更新saving.balance：

UPDATE TABLE saving s, time t 
SET s.balance = IF(t.currency_TYPE = ‘RMB’, s.balance + t.balance * t.interest) 
WHERE t.ID = 'input' 
AND s.User = t.User; 

然而，MySQL的給我ERROR 1064，出了什麼問題以及如何糾正呢？

Answer 1

你忘了你的IF函數和其他語法的東西:-)

這是第3爭論爲什麼你讓你的腳本不是在哪裏？像這樣：

UPDATE saving s 
INNER JOIN time t 
    ON t.ID = 'input' 
    AND t.User = s.User 
SET s.balance = s.balance + t.balance * t.interest 
WHERE t.currency_TYPE = 'RMB'; 

您將更新currency_type rmb的記錄！

OR

UPDATE saving s 
INNER JOIN time t 
    ON t.ID = 'input' 
    AND t.User = s.User 
SET s.balance = (t.currency_TYPE = 'RMB', s.balance + t.balance * t.interest, 0); 

Answer 2

您需要提及其他部分

UPDATE TABLE saving s, time t 
SET s.balance = IF(t.currency_TYPE = ‘RMB’, s.balance + t.balance * t.interest , 0) 
WHERE t.ID = 'input' 
AND s.User = t.User; 

Answer 3

試試這個：

UPDATE saving s 
INNER JOIN `time` t ON s.`User` = t.`User` 
SET s.balance = CASE 
        WHEN t.currency_TYPE = 'RMB' THEN s.balance + 
                t.balance * t.interest 
        ELSE s.balance -- Don't forgot this, default is NULL 
       END 
WHERE t.ID = 'input'; 

或者：

UPDATE saving s 
INNER JOIN `time` t ON s.`User` = t.`User` 
SET s.balance = s.balance + t.balance * t.interest 
WHERE t.ID = 'input' 
    AND t.currency_TYPE = 'RMB' ;