MySQL autoincrement on update

I'm trying to make a table for reviews on blogs. In my table, I want to have these columns:

• id
• total number of ratings
• total values of ratings

That way I can just get the average rating with simple math.

Is there a way that I autoincrement 1 to the column that has the total number of ratings, and开发者_StackOverflow社区 add the rating to the total number of total ratings without having to retrieve the information first?

For example, in PHP terms:

//instead of doing 
$column=$currentValue;
$column=$column+5;

//do
$column+=5;

is this possible with a MySQL update function if the columns are INT?

try something like this

update mytable set total=total+1;

You can use this statement:

UPDATE table1 SET total = IFNULL(total,0) + 1;

This will set total to 1 if it was null before and increase it otherwise.
This is a bit of a hack though, better to create column total as default '0'.