SQL 0 if negative value

Question

So I want to turn negative value's into a 0. I found 2 solutions that do exactly the same:

SUM(IF(ordered_item.amount < 0, 0, ordered_item.amount)) as purchases

And

SUM(CASE WHEN ordered_item.amount < 0 THEN 0 ELSE ordered_item.amount END) as purchases

They give me both the same result, but which would give me the best performance? And is there maybe a simpler solution to turn negatives into 0.

Answer 1

An alternate approach you could use is the GREATEST() function.

SUM(GREATEST(ordered_item.amount, 0)) as purchases 

Answer 2

You can define the field as "unsigned" so no conversion would be required

CREATE TABLE ordered_item ( 
order_id INT UNSIGNED NOT NULL AUTO_INCREMENT, 
amount INT UNSIGNED NOT NULL, 
PRIMARY KEY (`order_id `) 
); 

https://dev.mysql.com/doc/refman/5.0/en/integer-types.html