Question

I want to create an Event for Table :-

ACCOUNTS(id char(5),balance decimal(10,2), date_created date)

Value for the DATE_CREATED column will always be = NOW(), i.e. the date when the row was inserted in the table

I want that the balance for each row gets increased by 2% after every 31 Days, according to its DATE_CREATED column, i.e. after (DATE_CREATED+31 Days) for each row.

I wanted to know whether it is possible or not and if it is possible then what would be the code for it?

Answer 1

You’ll need to write an UPDATE statement that uses DATEDIFF and MOD

Try something like:

UPDATE Accounts 
SET Balance = Balance * 1.02 
WHERE DATEDIFF(now(),date_created) MOD 31 = 0;

And here is the SQL Fiddle.

You can schedule this to run daily. That’s probably your best approach.

Good luck.