如何使用TRIGGER自動在MYSQL中更新表

Question

我在mysql數據庫中有一張表，我正在計算基於interest + amount借入的New Owed Balcance ...我希望當利息被修改時，新的欠款發餘下的變化我使用觸發器，但它似乎並沒有當興趣改變

DELIMITER | 

CREATE TRIGGER updateloan BEFORE INSERT ON loan 
    FOR EACH ROW BEGIN 
    SET NEW.app_amnt_owed = NEW.app_intrst +NEW. app_ln_amnt; 
    END; 
| 

Answer 1

CREATE TRIGGER updateloan_update 
    BEFORE UPDATE ON loan 
    FOR EACH ROW 
    SET NEW.app_amnt_owed = NEW.app_intrst + NEW.app_ln_amnt;