插入行或更新（如果存在）（如果存在多个条件）

Question

I have a row that contains 3 fields:
day earnings person
1 3 1
1 7 2
1 4 3
2 6 1
2 9 2

The idea is that every person earns money/day, now what I want is to update the earnings for a day for a person, but if that person didn't have any earnings (the row for that person/day is not there) than insert the row

Example
day earnings person
1 3 1

In this case, it would update the row and add 1 earning:
day earnings person
1 4 1

If the original row was not preasent (so person and date did not exist) than insert a new row like:
day earnings person
1 1 1

I know that there exists the command INSERT ON DUPLICATE KEY UPDATE

But this works only for 1 unique index column (from what I read), I need it to work with day and person (2 columns).

I hope I explained correctly and someone can help. I know it's possible to do this from PHP but to avoid multiple queries (it's important) I would like to know if it's possible to make it in 1 query.

Here is what works if I only consider the date column (that is unique) any chance I can change it to work in my case?

INSERT INTO table (day, earnings, person)
VALUES ('1',earnings,1)
ON DUPLICATE KEY UPDATE
earnings = VALUES(earnings+1)

Answer 1

You can make it work by adding a composite unique key on both day and person.

ALTER TABLE `myTable` ADD UNIQUE (`day`,`person`);

And then

INSERT INTO `myTable` (day, earnings, person)
VALUES ('1',$earnings,1)
ON DUPLICATE KEY UPDATE
earnings = earnings + $earnings