php - 为什么sql中total_balance的结果为零？

Question

INSERT INTO transaction (account_name,dates,debit,credit ,total_balance)
VALUES('$account_name',curdate(),$debit,$credit,total_balance=$debit+$credit)
ON DUPLICATE KEY
UPDATE debit = debit + VALUES(debit), credit = credit + VALUES(credit)

这是查询，我不知道为什么总余额列中的余额显示为零，任何人都可以更改查询吗？

Id  Account_name    Date         Debit  Credit  Total_balance
21  revenue     2014-05-05        80      55    0
23  expense     2014-05-05       48000  90000   0
28  a/p         2014-05-05        800   1000    0

Answer 1

试试这个:

"INSERT INTO transaction (account_name,dates,debit,credit,total_balance)
    VALUES('$account_name',curdate(),$debit,$credit,($debit+$credit))
ON DUPLICATE KEY
UPDATE debit = debit + VALUES(debit), credit = credit + VALUES(credit)"