MySQL UPDATE Multiple IF Conditions

Question

I have a table which has been populated with incorrect data, so I need to switch some numbers around. I'm not sure if this would be the best way to go about it, but I'm thinking about using an UPDATE statement with multiple IF conditions. Something like:

UPDATE 
    `orders`
SET 
    `orderPriority` = 1
    IF(`orderPriority` = 2)
OR
    `orderPriority` = 2
    IF(`orderPriority = 3)
OR
    `orderPriority` = 3
    IF(`orderPriority` = 1);

Obviously this doesn't work, but my SQL skills are lacking here. Any help is appreciated!!!

Answer 1

UPDATE orders
    SET orderPriority = CASE WHEN orderPriority = 1 THEN 3
                             WHEN orderPriority = 2 THEN 1
                             WHEN orderPriority = 3 THEN 2
                        END
    WHERE orderPriority IN (1,2,3)