MySQL table setup counting a fields daily value changes

I have a table which at the moment just consists of an id, name, and number field. I would like to be able to record how much number field changes daily so that I may graph it later(ex. 10/01 5 , 10/02 20 etc). How do I set up the table in such a way t开发者_运维百科hat it will keep up with the daily changes?

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In my opinion what you are trying to do should be stored in another table

id, refId, delta, timestamp

Where refId is the id of the item in the table you described, delta is the change in number and timestamp is the time of the change.