更新前的mysql触发器

Question

hi i have one question for mysql trigger for before update i want when i call sql query for update at that time i want to get old value of column and add with new value

this is my table

i want to get wallet_balance column value before update and then add new value with old value and then update final value in this table using trigger

if i have 1800 and i get 100 then using trigger i want to update 1900 plese help me for this question

error

Answer 1

Try this:

DELIMITER $$
CREATE TRIGGER AddwalletValue
Before UPDATE ON admin_wallet  FOR EACH ROW
begin


New.wallet_balance = Old.wallet_balance + New.wallet_balance;



END;
$$
DELIMITER ;