max(x,y) in MySQL

For the following table (all columns are integers)

[id, value, best_value]

For a given id and value I want update it's row setting t开发者_如何学编程he best_value column to max(newvalue,best_value). I seached into the documentation but I dont see a function for doing so.

Thanks

You want GREATEST(x,y). Example, if the new value is 530:

UPDATE my_table SET best_value = GREATEST(530,best_value) WHERE id=123

You don't strictly need any such function,

UPDATE my_table SET best_value = new_value 
  WHERE id=123 AND best_value < new_value

would do the job about as well as AlienWebguy's answer :)