we have a social network that consists of several user types and we want to add $7.04 to all customer accounts to celebrate the USA holiday 4th of July.
I have used the following SQL command:
UPDATE `database`.`databasename` SET fCreditAmount = fCreditAmount + 7.04 WHERE eUserType = 'C'
It's hard to tell without more information, but it looks like you're adding $7.04 to every transaction in a user's history. So each user is getting
7.04 * numberOfTransactions in credit.
You should be adding a new transaction (an INSERT) in the desired amount. That way, each account will get the credit exactly once.
I certainly hope you didn't do this on your production database!